For which audience source is It possible to edit the audience definition within Adobe Target?

When testing Experience B in an A/B Activity with a QA link, the analyst does not see the targeted content for Experience B.
What could be the reason?

Which statement is true for all Experience Targeting activities?

An optimization team has decided to incorporate email into their testing strategy and wants to send emails to their list of subscribers. Their desire is to randomly send one of four different emails to users and see which email is the most effective.
How can this request be fulfilled?

Why must primary and secondary success metrics be determined pre-test and not chosen or adjusted after activation? (Choose two.)