ABC is a isosceles triangle. is AD the height of ABC? Explain.

(Yes or No) _ AD is (Perpendicular or not) _ to BC because _ A. 28^2 + 45^2 = 53^2
B. 28^2 + 53^2 ≠ 45^2
C. 28^2 + 45^2 ≠ 53^2
D. 28^2 + 53^2 = 45^2

The things in () are answers to fill the "_"