Explanation:

🧠 When your scenario involves routing calls based on the language spoken, the key requirement is to match the customer's language to the right agent who can communicate in that language. Salesforce (and similar platforms) offer built-in tools to handle this without needing custom code or external integrations.

✅ Correct Answer: B. Omni-Channel routing with skill mapping based on agent language proficiency

✔ Why this is correct:
Omni-Channel routing is a Salesforce feature that intelligently routes work (like cases, chats, or calls) to the most appropriate agents based on availability and skills.

With skill-based routing, you can:
✔ Define language skills (e.g., Spanish, French, Mandarin).
✔ Assign those skills to agents based on their language proficiency.
✔ Associate incoming cases, chats, or calls with required language skills.
✔ Let Omni-Channel automatically route the customer to an agent who matches the required skill.

This allows for real-time, automated, language-aware routing, with no need for complex custom development.

❌ A. Custom Apex code defining language detection and routing logic

✖ Why this is incorrect:

➤ Apex code can be used to build custom logic, but it’s not the preferred or primary method for routing calls based on language.
➤ It requires custom development, maintenance overhead, and is often unnecessary when out-of-the-box features like Omni-Channel and skill-based routing already support this use case.
➤ Apex also does not detect spoken language in a voice call — you’d need integration with external services for that.

❌ C. Phone Numbers configured with specific languages and automatic call routing

✖ Why this is incorrect:

➤ While you can assign different phone numbers to different languages (e.g., an English support line, a Spanish support line), this approach is very limited and doesn’t scale well.
➤ It doesn’t offer dynamic, real-time routing based on detected or selected language — it assumes the caller already dials the correct number.
➤ This method lacks flexibility and doesn’t account for customers who might use the wrong line or need multilingual support.

❌ D. Integrated Speech-to-Text (STT) and language identification tools for real-time routing

✖ Why this is incorrect:

➤ While STT and language identification technologies do exist and could potentially help, they are not native Salesforce features and require external tools and custom integrations.
➤ Implementing this would require significant effort and technical expertise — far more than using built-in skill-based Omni-Channel routing.
➤ Also, speech-to-text introduces latency and possible inaccuracies in real-time voice routing.

🎯 Final Takeaway:
B. Omni-Channel routing with skill mapping is the standard, scalable, and efficient way to handle language-based routing in Salesforce or similar systems. It uses built-in capabilities to assign the right agent based on defined skills — including language — and ensures fast, accurate service.