Which two practices should the marketing manager employ?

The marketing manager of Northern Trail Outfitters is interested in A/B testing emails in order to increase subscriber engagement.

Which two practices should the marketing manager employ? (Choose two.)
A . Offer a special discount for opening the email.
B. Use a large sample size.
C. Wait at least 24 hours before declaring a winner.
D. Test multiple variations concurrently.

Answer: B,C