Grayson is making cookies and, knowing that he has a history of burning every batch of cookies that he's ever made, he decides to set the timer to remind himself when they are ready. This strategy provides a distinctive that will trigger Grayson's prospective memory to take the cookies out of the oven.

Retrieval cue.

Explanation:

Grayson setting the timer to remind himself when the cookies are ready to be put off from the oven is using a strategy called retrieval cue.A retrieval cue is a stimulus that triggers recall and recognition of memory. The phenomenon of retrieval cue relies on additional information that is given to person to recall a particular event or information.Without additional output of information or reminder, retrieval cue cannot be triggered.