Which term refers to an unlearned reaction to a stimulus that occurs without previous conditioning

A)  unconditioned response
B)  unconditioned stimulus 
C)  conditioned response
D)  conditioned stimulus

Unconditioned Response

A natural, automatic reaction to a stimulus that occurs without previous conditioning.

Unlearned Reaction

An instinctual or reflexive response that occurs without prior learning or experience, typically innate and common in human and animal behavior.

Previous Conditioning

The learning or training that an individual has received in the past, which influences their current behavior or reactions.