Muir and Mitchell's Visual Pattern Discrimination Tests on Kittens Raised

Muir and Mitchell's visual pattern discrimination tests on kittens raised in an environment devoid of certain visual stimuli demonstrated that:

A) while the sensation abilities of the kittens raised in the deprived environment were affected, their perceptual abilities were not.
B) the "critical period" in the kittens' perceptual development was not as critical as previous researchers had thought it to be.
C) kittens raised in the deprived environment had a specific pattern of feature detectors in their brains.
D) kittens raised in the deprived environment were able to discriminate test patterns as well as kittens raised in a normal environment.