When should a system administrator consider using the Salesforce AppExchange? (Choose two.)

A user asks for a checkbox to be automatically ticked if the annual revenue field is greater than a million.
Which formula to trigger a workflow would satisfy this requirement?

Universal Containers wants to test code against a subset of production data that is under 5 GB. Additionally, Universal Containers would like to refresh this sandbox every weekend.
What type of sandbox should be used to accomplish this?

Sales representatives want to capture custom Feedback record details related to each Account. The sales reps want to accomplish this with minimal clicks on the Salesforce Mobile Application.
Which two solutions should be recommended in order to meet this requirement? (Choose two.)

Ideally, who should be in charge of logging all changes in production?