Explanation:

To meet the goal of improving response time and managing load on a downstream API, the Circuit Breaker policy offered in Anypoint API Manager is the most effective and recommended solution.
MuleSoft provides an out-of-the-box Circuit Breaker policy that can be applied to API instances. This policy supports advanced configurations, including thresholds for opening, closing, and half-opening the circuit based on error rates and time intervals. These align well with the scenario:
✑ Circuit Open when errors exceed 10 per minute for 3 minutes.
✑ Circuit Half-Open to test the endpoint with limited requests (e.g., 1 per minute).
✑ Circuit Closed when stability is detected (less than 1 error/min for 5 minutes).

Option C enables this strategy with minimal custom development and centralized governance through API Manager.

✑ Option A (custom policy) is overly complex for this use case.
✑ Option B (monitoring alerts and retry strategy) lacks automatic circuit breaking.
✑ Option D (YAML config in Mule app) is non-standard and may lead to inconsistencies across deployments.
Using the native Circuit Breaker policy ensures better maintainability, observability, and alignment with platform best practices.

Explanation

Correct Answer: A Non-Mule application

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>> All type of Mule applications (Mule 3/ Mule 4/ with APIkit/ with Custom Java Code etc) running on Mule Runtimes support the Embedded Policy Enforcement on them.

>> The only option that cannot have or does not support embedded policy enforcement and must have API Proxy is for Non-Mule Applications.

So, Non-Mule application is the right answer.

Explanation

Correct Answer: JSON threat protection

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Fact: Technically, there are no restrictions on what policy can be applied in what layer. Any policy can be applied on any layer API. However, context should also be considered properly before blindly applying the policies on APIs.

That is why, this question asked for a policy that would LEAST likely be applied to a Process API.

From the given options:

>> All policies except "JSON threat protection" can be applied without hesitation to the APIs in Process tier.

>> JSON threat protection policy ideally fits for experience APIs to prevent suspicious JSON payload coming from external API clients. This covers more of a security aspect by trying to avoid possibly malicious and harmful JSON payloads from external clients calling experience APIs.

As external API clients are NEVER allowed to call Process APIs directly and also these kind of malicious and harmful JSON payloads are always stopped at experience API layer only using this policy, it is LEAST LIKELY that this same policy is again applied on Process Layer API.

Reference: https://docs.mulesoft.com/api-manager/2.x/policy-mule3-provided-policies

Explanation:

Let’s break down the key roles:
API Consumer
The entity (e.g., a business unit or external system) that needs to use the API
API Client
The actual software (e.g., app, script, integration) that sends requests to the API
API
The interface that defines how clients interact with the backend logic
API Implementation
The backend logic or service that processes the API requests and returns responses

🔄 Flow of Invocation:
API Consumer decides to use an API.
They create or configure an API client (e.g., a Mule flow, Postman collection, or frontend app).
The API client sends requests to the API endpoint.
The API implementation receives and processes the request, returning a response.

This is a classic separation of concerns in API-led architecture:
Consumers don’t directly interact with implementations.
Clients are the bridge between consumers and APIs.

❌ Why the Other Options Are Incorrect:
A Reverses the relationship — consumers don’t create implementations.
B Misrepresents the flow — clients don’t create consumers.
D Incorrect actor relationships — clients don’t create consumers, and the flow is reversed.

🔗 Reference:
MuleSoft API-led Connectivity Overview
MuleSoft Docs – API Manager and Client Interaction

Explanation

Correct Answer: The API policy is defined in API Manager for a specific API instance, and then ONLY applied to the specific API instance.

***************************************** >> Once our API specifications are ready and published to Exchange, we need to visit API Manager and register an API instance for each API.

>> API Manager is the place where management of API aspects takes place like addressing NFRs by enforcing policies on them.

>> We can create multiple instances for a same API and manage them differently for different purposes.

>> One instance can have a set of API policies applied and another instance of same API can have different set of policies applied for some other purpose. >> These APIs and their instances are defined PER environment basis. So, one need to manage them seperately in each environment.

>> We can ensure that same configuration of API instances (SLAs, Policies etc..) gets promoted when promoting to higher environments using platform feature. But this is optional only. Still one can change them per environment basis if they have to.

>> Runtime Manager is the place to manage API Implementations and their Mule Runtimes but NOT APIs itself. Though API policies gets executed in Mule Runtimes, We CANNOT enforce API policies in Runtime Manager. We would need to do that via API Manager only for a cherry picked instance in an environment.

So, based on these facts, right statement in the given choices is - "The API policy is defined in API Manager for a specific API instance, and then ONLY applied to the specific API instance".

Reference: https://docs.mulesoft.com/api-manager/2.x/latest-overview-concept