Answer:
Option D
Step-by-step explanation:

For F=77°F

All possibilities = 9!
possibilities that harry sits at an end = 8! + 8!
possibilities that harry doesn't sit at an end = 9! - 8! -8!
The answer you want will be 10.
Hope it helps!!
The formula for finding the total interior angle measure is:
180(n-2)
n is the number of sides.
180(25-2) = 4140
So each interior angle would be: 165.6
4140/25 = 165.6
Hope this helps :)