Explanation:

What is the “Component” checkbox?

On the Product record, there’s a field called Component (API: SBQQ__Component__c).

When Component = TRUE, Salesforce CPQ:
Hides the product from the Product Selection page when users add products manually in the Quote Line Editor.
Still allows the product to appear as a Product Option inside bundles.

That’s exactly what UC wants:

The bundles should be visible on the Product Selection page → so users can choose the bundles.
The option products should be hidden from the Product Selection page → so users cannot add them directly outside their bundles.

Hence, you mark those option products as Component = TRUE.
This is a standard CPQ design pattern for option-only products.

❌ Why Other Options Are Incorrect

B. Select the Hidden for any Product that is a Product Option for the bundles.

✘ Incorrect.
There is no standard “Hidden” checkbox on the Product object for this purpose.
The correct method is the Component checkbox.

C. Select the Selectbox on each product option and mark the Product inactive

✘ Incorrect.
Inactivating a product makes it unavailable everywhere, even in bundles.
UC wants these products available as options in bundles, so they should remain active.

D. Select the bundle on each Product option and mark the Product inactive

✘ Incorrect.
Same issue as C → inactivating the product removes it from bundles, which UC doesn’t want.