Greg is 10 months old, and he refuses to crawl across a visual cliff even though his mother is encouraging him to do so. When he was 6 months old, he squirmed across it without hesitation. What has changed for Greg

his perception of depth has changed, he has realized that if he crawls along the cliff he may likely suffer a fall.

Explanation:

His behaviour was based on  experimental findings of  Visual cliff  hypothesised  by   Gibson and Walk;  that dept perception is inborn or innate and not acquired.  The fact that  he was  not able to crawl across the visual cliff, at 10 months  contrary to his ability to  do so at 6 months, is an indication that  his   perception of  depth,  has changed.  The evidence that he achieved this   at 6 months without hesitation shows that the use of his sense of vision  to perceive  depth  is innate, and not acquired.

your answer will be c. sorry if im wrong: )