Answer:
The correct answer is letter "A": Screening mechanism.
Explanation:
The screening mechanism is the activity in which people identify good qualities in others by evaluating their actions and matching them with their own behavior so they can eventually qualify those other people as suitable for them or not.
In the example, Sally must consider a good practice to give generous tips to waiters since only if Andy, her date, does such a thing, she will consider dating him again. What Sally conducted is an example of a screening mechanism.