Use the Following Information to Answer the Next Few Questions

Use the following information to answer the next few questions.
While walking your dog one night, you notice that there are few animals making noise compared to the day. This piques your interest and you decide to perform a literature search. You discover that the 24-hour biological clock is a conserved evolutionary adaptation across many taxa, and is typically synchronized with periods of light and dark, where the animals are alert in the light periods and sleeping during the dark periods. The group of neurons that links the biological clock to environmental cues of light and dark is called the suprachiasmatic nucleus (SCN) .
-In birds and mammals, the hormone that affects the sleep/wake cycle is

A) TSH.
B) norepinephrine.
C) epinephrine.
D) dopamine.
E) melatonin.