In the Visual Cliff Experiment by Eleanor Gibson and Richard

In the visual cliff experiment by Eleanor Gibson and Richard Walk, most 6- to 12-month-old babies encouraged to crawl onto the deep side of the visual cliff would:

A) crawl onto the cliff side.
B) not crawl onto the cliff side.
C) crawl onto the cliff side only when their mothers called them.
D) not crawl onto the cliff side but showed significant increases in heart rate, indicating anxiety about the situation.