Three-year-old jonathan saw fireworks that were repeatedly followed by loud fear-producing explosive sounds. the mere sight of fireworks first began to trigger a learned fear reaction in jonathan during the process of

The correct answer is classical conditioning. 

Classical conditioning can be defined as the process whereby a conditioned stimulus (such as the sight of fireworks) is paired with and occurs before an unconditioned stimulus (explosive sounds), until the conditioned stimulus (the sight of fireworks) alone is able to bring about a response (such as fear reaction).