Answer:
D ) feedback
Explanation:
When we use an air conditioner, it get turn off when reaches its required temperature and when the house warm up the air conditioning unit turns on again, that is an example of feedback.
The given condition is an example of negative feedback because in negative feedback, any change in the input is opposed by generating an output. Here also, warming up of house (change in one direction) allows the air conditioning unit turns on and it gives cool air (opposing that change).
Hence, the correct option is "D".