(A) So a channel can share in monetization of your content
(B) To require a manual review of all claims on their uploads
(C) So a channel can use your material without getting automated claims
(D) To prevent the channel from receiving copyright takedowns
You would want to whitelist a channel in order to allow a channel to use your material without getting automated claims.
This question is a part of the Check your Knowledge section of the “Control your claims workflow” lesson from the YouTube Content Ownership course.