The Lens on a Telescope Has a Diameter of 200 $\pi$

Multiple Choice

The lens on a telescope has a diameter of 200 in. Find the area of the lens of the telescope. Give the exact value.

A) 200 $\pi$ in ²
B) 10,000 $\pi$ in ²
C) 80,000 $\pi$ in ²
D) 160,000 $\pi$ in ²
E) 400 $\pi$ in ²