Final answer:
The individual dose would be 60 mg (option d).
Step-by-step explanation:
The student is taking a total of 180 mg of medication each day and it is ordered to be taken tid, which stands for 'three times a day'. To determine the individual dose, we divide the total dose by the number of times it is taken in a day. In this case, 180 mg divided by 3 is 60 mg. Therefore, the individual dose would be 60 mg (option d).