Only One of the Following Teaching Practices Is Consistent with What

Only one of the following teaching practices is consistent with what we know about working memory.Which one?

A) Mr.Adams tells his students that, with practice, they will be able to do complicated long division problems in their heads.
B) Ms.Borelli tells her students that they should try to focus on main ideas rather than try to remember every detail.
C) Ms.Fisher suggests that students in her Russian class listen to Russian tapes while they sleep.
D) Mr.Vandenberk urges his students to put information for tomorrow's test in their "short-term memories."