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

A large bank would like to test different Call To Action Buttons on their email. Which composer should they use to execute the test?

The optimization team at an e-commerce company recently learned that if the company does not sell a large proportion of its discontinued products, the company will incur an accounting charge that will materially affect the company's quarterly earnings.
The discontinued products are sold at a discount on a separate website and domain that currently do not have Adobe Analytics or Adobe Target. The e-commerce website does have Adobe Analytics and Adobe Target.
The optimization team decides to run an experiment to promote the discontinued products website. They add a "SALE1' link to the e-commerce website's main navigation. The "SALE* link also links to the discontinued products website.
The optimization team wants to use an A/B test to see if adding this new link to the e-commerce site's main navigation causes visitors to visit the discontinued products website.
What should be the goal of the A/B test on the main website?