Assuming That the Students Below Studied Only at the Times

Assuming that the students below studied only at the times described and that all other things (intelligence, motivation, and previous knowledge of psychology) are equal, who is most likely to do the best on this exam?

A) Otto, who studied the textbook for ten hours straight during the day today
B) Omar, who studied two hours each day for the last five days (including today) for a total of ten hours
C) Ophelia, who studied ten hours straight last Saturday
D) Olivia, who studied two hours each day for five consecutive days two weeks ago