Feeling pain, hunger, thirst, sleepiness, and being aware of our thoughts and emotions are all examples of stimuli.
a. psychoactive
b. hypnotic
c. external
d. internal

Internal stimuli

Explanation:

Internal stimuli are the stimuli that work as a protector for an animal and maintain the homeostasis. The biological responses like thirst and hunger give a response to the lack of water and food.

Some internal responses protect a person from an internal illness or pathogen. When some pathogen attack internally some virus, our body raise the temperature and response in fever to protect the body.

Fever helps the body not to activate the invading virus. Fever is the response internally that helps the body not to invading some pathogen.  

its d. you give me brainliest