The correct answer would be Conditioned Stimulus.
Students soon notice that they start to feel anxious when professor Kraig turns off the projector. In terms of Classical conditioning, Prof. Kraig turning off the projector is a conditioned stimulus.
Explanation:
Classical conditioning is a concept in psychology which tells us that there are two main stimuli. One is Conditioned stimulus and the other is unconditioned stimulus.
Conditioned stimulus in classical conditioning is a neutral stimulus, which is when associated with the unconditioned stimulus, triggers or generates a conditioned response.
So here turning off the projector by the professor is a conditioned stimulus, which is when associated with the unconditioned stimulus which is taking quiz, then a conditioned response is generated or triggered which is anxiety in students.
Learn more about Conditioned Stimulus at:
https://brainly.com/question/4734131
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