Tom Is Going to Quit His Job to Pursue His

Tom is going to quit his job to pursue his PhD in economics, which will take him 6 years to complete. He currently makes $55,000 per year as a high school teacher. While going to school, he will receive a stipend of $24,000 per year plus $6,000 per year to help cover food and rent. His living expenses are the same regardless of what he does. What is Tom's opportunity cost of pursuing his PhD?

A) $150,000
B) $180,000
C) $186,000
D) $330,000