Imagine that you flinch after seeing lightning because in previous instances the lightning is followed by thunder, which scared you. In this scenario, lightning can be interpreted as being a(n):

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

conditioned stimulus ( C )

Explanation:

A conditioned stimulus is a previously neutral/unconditional stimulus that has been learned by a person or something and the person responds to in a certain way anytime is occurs .

while an unconditional stimulus occurs naturally and triggers a person to respond spontaneously without learning the stimulus previously.

so when you finch after seeing lightning every time you see the lighting is a certain way of response because you have learnt overtime that the lightning is usually followed by a thunder.