Which of These Is a Reason to Spread Out Studying

Which of these is a reason to spread out studying over time instead of studying all at once?

A) Studying all at once makes you likely to underestimate your memory of facts.
B) Spreading out your study time will help you practice retrieving a memory.
C) It is easier to remember something you learned a few days ago than something you learned more recently.
D) Spreading out your study time gives you more time to repeat the text in your head.