Answer:
D) classical conditioning, operant conditioning, and observational learning.
Step-by-step explanation:
It is unusual for a phobia to start after the age of 30 years, and most begin at the earliest times of ones life, the teenage years, or early adulthood. They can be triggered by a stressful experience, a frightening event, or a parent or household member with a phobia that a child can 'learn.