In Research Described by Your Authors, Participants Were Asked to Complete

In research described by your authors, participants were asked to complete a specific task. In some cases, they were told that they would complete this task again after some sleep. In other cases they were not told, but allowed to sleep. In still a third group, they were not warned about taking the test again and were not given a chance to sleep. What was the task that these research participants completed?

A) the Stroop color test
B) learning word pairs
C) remembering lists of numbers
D) identifying pictures of movie stars and other famous persons