It might be B I might not be right
You can use Pythagoras theorem to find the radius.
r^2 + 8^2 = 10^2
r^2 + 64 = 100
r^2 = 36
r = 6
-15 < 3n < 6
Divide all sides by 3
-5 < n < 2
Now you need all integers between -5 and 2.
-4, -3, -2, -1, 0, 1
280 + 220 = 500 is the answer