Two points P and Q are at the distance of x and y (where y > x) respectively from the base of a building and on a straight line. If the angles of elevation of the top of the building from points P and Q are complementary, then what is the height of the building?

A

xy

B

$$\surd(\frac{y}{x})$$

C

$$\surd(\frac{x}{y})$$

D

$$\surd(xy)$$