Final answer:
The median of the given data: 73, 74, 75, 77, 79, 82, 84, 85, 91 is 79.
Step-by-step explanation:
To find the median of the given data: 73, 74, 75, 77, 79, 82, 84, 85, 91, you first need to arrange the data in ascending order: 73, 74, 75, 77, 79, 82, 84, 85, 91. Since there are 9 numbers in total, the median will be the middle number. In this case, the middle number is 79, so the answer is 79 (option a).