In Preparing Her Clients for Sleep, the Nurse Dims the Lights

In preparing her clients for sleep, the nurse dims the lights, as exposure to darkness:

A) causes an increase in the reticular activating system (RAS) .
B) causes a decrease in stimulation of the reticular activating system (RAS) .
C) reduces the amount of melatonin secreted by the pineal gland.
D) increases the amount of noradrenaline by the pineal gland.