Sixth Graders Were a Part of a Study Examining Analytical

Sixth graders were a part of a study examining analytical reasoning in solving puzzles in October. They were then asked to be a part of a completely different study in March that also tested their analytical skills in solving word problems. The researcher in the most recent study was very surprised at how developed their analytical skills were. This is most likely due to:

A) fatigue effects.
B) carryover effects.
C) practice effects.
D) sensitization effects.