Answer:
D. stimulant; dopamine
Step-by-step explanation:
Stimulant is a type of drugs that will improve the activity central nervous system, This will make you heightened your senses and will most likely feel alert with a significant improvement in your concentration. Stimulant commonly used as performance enhancement.
Dopamine on the other hand, will stimulate the pleasure centre of the brain. It will make you feel excited and happy. You can actually increase your dopamine without a drug. Simply by doing something you feel as rewarding or doing an activity with someone you like could actually increase the level of your dopamine.