Answer:
The correct answer is option A) Retrieval.
Step-by-step explanation:
The reason why Treysen was frustrated because he could not retrieve the kind of minute information that he is not supposed to forget. He remembers all the other information and the one thing he does not expect himself to forget has skipped his mind.
This failure in terms of retrieving the name of the restaurant was frustrating him.
I hope the answer is helpful.