Answer:
683
Step-by-step explanation:
if you don't have a Unit Circle yet, this is a good time to get one, you can find many online, check maybe in yahoo images, or google images.
Check the picture below.
notice the section encircled in purple.
Class A - IQ1 - 76 - IQ3 - 81 - IQR - 5
Class B - IQ1 - 75 - IQ3 - 82 - IQR - 7
Class B is more variated than Class A.
The answer is D because to use Pythagorean Theorem it has to be a right triangle.