Respuesta :
Correct answer is B!
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If you see meaning of "Unconditioned stimulus", you will see the right answer, firstly what does "Unconditioned Stimulus" means, it means any stimulus that naturally evokes a specific response; see also conditioning. If I would go with choices I would choose correct answer B.
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Hope this helps!
Brainliest would be great!
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I COULD BE WRONG, IF I'M PLEASE CORRECT ME!
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With all care,
07x12!