Answer:
Option (d) is correct.
Explanation:
Opportunity cost refers to the benefits that would be obtained from the next best alternative. It can be measured in monetary terms as well as in non-monetary terms.
In our case, the opportunity cost of attending college is the loss of money income that a person would be earn. All the other costs in the options are consider as the explicit costs such as tuition, books, travelling expenses, psychic costs, etc.