Based on fact that the rat exhibits a fear response to light, the conditioned stimulus in the study must be the flashing light.
This is a stimulus that a research subject does not react to at first, but learns to react to over time.
The rat did not react negatively to the flashing light at first, but as time went on, it began to fear it. It had therefore developed a reaction to the flashing light
Find out more on conditioned stimulus at https://brainly.com/question/24868138.
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