Colobine Primates Are Well Adapted for Eating Leaves

Colobine primates are well adapted for eating leaves.What leaf-eating traits have evolved in these monkeys?

A) They have cheek pouches for saving leaves to be consumed later,analogous to a cow chewing cud.
B) They have low,rounded teeth that allow the crushing of leaves to obtain more nutrients from them.
C) They are very arboreal,have high,pointed molars good for shearing leaves,and a three or four chambered stomach similar to that of a cow.
D) They have prehensile tails that allow them to more easily feed and move about in the high canopy of the rainforest.