A stimuli is an environmental cue from either the internal environment or the external environment The stimuli is detected by receptors, which pass a signal along to the brain or spinal column through sensory neurones. The brain and spinal column make up the CNS, and they coordinate the body's response to the stimuli.
The Answer is A. it's pretty much common sense yeah a depressed person or suicidal person can be put into peer pressure and earn bad grades and have poor study habits, that can be normal. but Suicidal behavior is a serious concern