The answer is: C. were superior at learning mazes.
From the result of this experiment, we can learn the different possibilities of learning methodologies that are applicable by mammals.
When combining the cages with colorful patterns, platforms, and ladders, the rat subjects in the experiments are trained to utilized different part of their brains when they try to solve a certain problems. The study suggested that this is the reason why rats in enriched cage were superior at learning mazes.