Answer:
A) opportunity cost
Step-by-step explanation:
Opportunity cost refers to the value of next option available which is forgone in order to choose the current option. As the benefit is more in current option then the option forgone, the marginal benefit is basically the difference between the two options.
As for example if you earn $10,000 in current job and the opportunity cost is $8,000, then the marginal benefit is $2,000.
because if current job was not chosen then it would have earned $8,000, but the additional amount earned = $2,000.