In a Study Conducted by Haber and Barchas (1983), Monkeys

In a study conducted by Haber and Barchas (1983) , monkeys were injected with amphetamine, a central nervous system stimulant. Comparison of the drug's effects on the dominant versus submissive monkeys demonstrated that the effects of brain chemicals such as drugs are

A) different for individual animals depending upon their place in the social hierarchy.
B) the same for all animals regardless of their place in the social hierarchy.
C) the same for all animals except for those with a biological predisposition for aggression.
D) different for individual animals but the differences appear to be random.