Correct: C , Audience Builder

In Marketing Cloud Audience Builder, you can segment your subscribers in multiple ways. Using advanced segmenting, you can better target your sends, and you get a more immediate and deeper understanding of your customer attributes and behavior. You can use Audience Builder with any Marketing Cloud account type. Also, Audience Builder provides some additional features for Enterprise 2 configurations, including business unit filters. Contact your Marketing Cloud account representative about enabling this feature for your account.