Answer:
Sarah is asking each department head how long they can be without their primary system. Sarah is trying to determine the Recovery Time Objective (RTO) as this is the duration of time within which the primary system must be restored after the disruption.
Recovery Point Objective is basically to determine the age of restoration or recovery point.
Business recovery and technical recovery requirements are to assess the requirements to recover by Business or technically.
Hence, Recovery Time Objective (RTO) is the correct answer.