Randy Exercises More Than Most People and Continues to Train

Multiple Choice

Randy exercises more than most people and continues to train even when he has a cold or an injury. His friends joke that Randy seems addicted to exercise. According to Focus on Neuroscience, Randy's compulsive exercising:

A) may be due to the involvement of his brain's opioid system and the production of endorphins.
B) is an indicator of decreased levels of dopamine and increased risk of Parkinson's disease.
C) may be due to the involvement of his limbic system and the production of acetylcholine.
D) is an indicator of the overproduction of dopamine and an increased risk of schizophrenia.