Out of the Conditions Tested, Average Final Recall Was Highest

Out of the conditions tested, average final recall was highest in which of Roediger and Karpicke's (2006) groups:

A) Repeated test at a 5-minute delay
B) Repeated study at a 1-week delay
C) Repeated test at a 1-week delay
D) Single test at a 5-minute delay
E) Single test at a 1-week delay