How are the test audiences for an A/B test selected? (Choose 2)

How are the test audiences for an A/B test selected? (Choose 2)
A . The test administrator chooses which subscribers to place in each audience
B. The system automatically uses 15% of the population for each audience
C. The system randomly places target subscribers into the selected audiences
D. The test administrator selects a percentage or a fixed number of target subscribers from the total for each audience

Answer: C,D