The Cats That Escaped from Thorndike's Puzzle Boxes Got Faster

Multiple Choice

The cats that escaped from Thorndike's puzzle boxes got faster at escaping over time,but the change was quite gradual.What did Thorndike interpret about this pattern of behaviour change

A)  Learning occurs as a result of gradual strengthening of rewarded behaviours. 
B)  Learning is enhanced when there is time for reflection in between trials. 
C)  Cats require exposure to experienced models to learn appropriately. 
D)  Cats are capable of thinking and understand the problems they solve.