Answer:
Option C
Step-by-step explanation:
Add all grades together:
79 + 80 + 92 + 92 + 81 + 100 + 88 + 98 + 71 + 100 + 91 + 90 = 1062
Divide the total by the number of grades in the set:
1062/12 = 88.5
The average of the grades is 88.5%, therefore Option C should be the correct answer.
