(B) Sequences of user actions
(D) Ad type
You can create Custom Segments based on Dimensions like Browser, Language, Location, OS, etc. Metrics like Avg. Time on Page, Session Duration, etc. Sequences of user actions, and Conditions. But, you cannot create Custom Segments based on Ad Type.
This question is a part of the Google Analytics Individual Qualification. You can get all the answers with detailed explanation for this exam in our Google Analytics Individual Qualification Exam Answers page.