Answer:
a.Payment for meals
Step-by-step explanation:
Opportunity cost is referred to as the next best alternative.
Opportunity cost means the benefits foregone of the non chosen alternative when an alternative is chosen from the available set of options which includes the non chosen option.
For e.g storage of money at home has an opportunity cost in the form of loss of interest had the same money been invested elsewhere apart from assuming the risk of loss of theft.
In the given case, the opportunity cost of being a full time student at a university instead of working full time at a job includes the opportunity cost in the form of income from that full time job in addition to specific expenses incurred for being a full time student such as Payment for tuition, Payment for books.
Thus, payment for meals represents a common cost which would've been incurred anyway irrespective of whether one attends full time college or does a full time job.