From Observations of the Adult Behavior of Surrogate-Raised Monkeys, It

From observations of the adult behavior of surrogate-raised monkeys, it has been concluded that:

A) inanimate surrogates can make perfectly acceptable mother substitutes for infant monkeys.
B) an adequate amount of milk is both necessary and sufficient for infant monkeys' normal development.
C) social interaction with other monkeys is necessary for infant monkeys' healthy social development.
D) an adequate amount of contact comfort is both necessary and sufficient for infant monkeys' normal development.