Refer to the exhibit.

Option D is the correct answer because, in the context of Auto-RP, sparse-dense mode allows the router to forward Auto-RP messages. Auto-RP uses dense mode multicast groups (224.0.1.39 and 224.0.1.40) to advertise RP mapping information, so enabling sparse-dense mode on the interface ensures that it can process both types of multicast traffic. References: Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) official course materials, which can be found here.