Answer:
Retrieval
Step-by-step explanation:
Retrieval: In psychology, the term retrieval is defined as the phenomenon in which the information present in an individual's memory can be recalled. The information that is being recalled can be of images, events, and feelings that are being stored in the memory of the person.
If in case a person is not able to recall a piece of information then it doesn't signify that the information is not present in his or her memory but it is due to the failure in the retrieval process.
In the question above, a problem with retrieval was the cause of Treysen's frustration.