Josefa and Ann Have Birthdays One Month Apart

Josefa and Ann have birthdays one month apart. Josefa's birth date puts her in first grade while Ann's puts her in kindergarten. When they are tested on a recall test at the end of the school year, Josefa remembers more items than Ann. What would you tell Ann's mother about this result?

A) She should be concerned about Ann's memory abilities, as she appears to be delayed compared to Josefa.
B) She should report Ann's kindergarten teacher, as she doesn't seem to have been taught what she should have during kindergarten.
C) Ann was probably having a bad day when the test was conducted, and she shouldn't worry too much.
D) These results are to be expected because participation in school tends to help a child learn strategies useful in recall tasks.