The loud noise made by the car backfiring is an unconditioned response .
Option D is correct.
An unconditioned response is an automatic reaction to a stimulus. In Pavlov's experiments, salivation is an essential response for dogs to seek food. Other examples of unconditioned responses are: Panting in pain after being stung by a bee. Remove hands after touching the hot plate on the stove. Jump to loud noises. Unconditional responses are natural and automatic. Unconditional responses are innate and require no prior learning.
Conditioned responses are behaviors that do not occur naturally, but must be learned by individuals by combining neutral and strong stimuli. A strong stimulus is one that does not require learning or conditioning to respond appropriately.
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