When Placed in a Cage with a Soft Cloth "Mother

When placed in a cage with a soft cloth "mother" and a wire "mother" equipped with a feeding nipple, rhesus monkeys:

A) spent more time hanging on the soft cloth mother, even though the wire mother provided nourishment.
B) spent more time hanging on the wire mother, primarily because it was equipped with a feeding nipple.
C) refused to eat altogether.
D) refused to spend any time on the soft cloth mother because it offered no nourishment.