Definition: You are given a question on high school psychology. You are also given 4 answer options (associated with "A", "B", "C", "D"), out of which only one is correct. You need to answer the question by selecting the correct option. You should only answer with the choice letter, not the whole answer.
Input: What is the first step in any example of classical conditioning?
(A)Following a response with a reinforcement or a punishment (B)Reinforcing an organism for a behavior similar to the desired behavior (C)Pairing an unconditioned stimulus with a conditioned stimulus (D)Rewarding a behavior with an unconditioned stimulus, such as food

C