Answer:
an emotion
Step-by-step explanation:
In simple words, emotions refers to the mental state of an individual that arises from the chemical changes due to some good or bad experiences that an individual faces. The arousal of emotions into the brain is directly related to the nervous system of the body which reacts differently on different situations.
Many research have been made for emotions but still no specific definition has been established, therefore, emotions is sometimes seen as feelings, behavior and body language etc.
Thus, from the above we can conclude that the correct option is D .