Suppose a researcher wants to determine whether someone is afraid of cats. Of the following, which would be the most reasonable approach?

A. Present a photo of a cat and see whether it elicits a startle reflex.

B. Present a photo of a cat and then a loud sound.

See whether the photo enhances the usual startle reflex.

C. Present a loud sound and then show a photo of a cat.

See whether the photo calms the person after the startle reflex.

D. Present a loud sound to both a person and a cat and see which one shows the greater startle reflex.

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