Which statement is true regarding campaign hierarchy?

What is the primary benefit of utilizing a platform option?

A Campaign developer notices that targeting approval and content approval notifications are not being sent.
What should the developer verify to resolve this situation?

An Adobe Campaign Classic Developer needs to programmatically create a workflow based on a workflow template, set an instance variable, and start the workflow. Which out-of-the-box method should be used in this case?

A Campaign developer is configuring an exclusion that takes two queries as input.
Query 1: Select customers with email address
Query 2: Select customers who do not want to be contacted
Customers who do not wish to be contacted must be removed. In a test run of the exclusion, the workflow raises the following error:
"You must define the main set for exclusion 'Remove Suppressions'." How should the campaign developer solve this issue?