All the vertices of a rectangle lie on a circle of radius R. If the perimeter of the rectangle is P, then the area of the rectangle is

A

$$\frac{P^2}{16} - R^2$$

B

$$\frac{P^2}{8} - 2R^2$$

C

$$\frac{P^2}{2} - 2PR$$

D

$$\frac{P^2}{8} - \frac{R^2}{2}$$