(A) Users, Time, Day
(B) Day Index, Hour, Sessions
(C) Hour of Day, Sessions, Transactions
(D) Day of Week, Hour, Ecommerce Conversion Rate, Sessions
The Custom Metrics you should choose are Hour of Day, Ecommerce Conversion Rate, and the number of Sessions. The Custom Dimension you should choose is the Day of Week. This will allow you to check the corresponding day of the week and hour of the day for the sessions which had the highest Ecommerce Conversion Rate.
This question is a part of the Assessment 2 section of the Google Analytics for Power Users course. You can find all the questions from all the four assessments with detailed explanation for this exam in our Google Analytics for Power Users Assessment Answers page.