What step type should be used in engagement studio if a user wants to branch prospects down two paths based on actions taken on a marketing asset?

The correct answer is C. Trigger

Trailhead:
“Use trigger steps to define paths in your engagement program based on prospect actions. Triggers listen for an event to occur within a specified period of time. This means that Trigger logic doesn’t evaluate a prospect’s actions for all time. Instead, during the window of time you’ve chosen for the step, the program looks to see if that event has occurred at any time since the prospect entered the program.

A trigger is there to answer the question, “Has the prospect done this?” A trigger is a branch point, so whether a prospect has taken an action or not determines the branch they will continue down.”