The cross -section of a road partly in banking and partly in cutting is shown in the given figure. The area of the shaded portion is

Q. The cross -section of a road partly in banking and partly in cutting is shown in the given figure. The area of the shaded portion is

A.            (b – rd)²/(r – s)

B.            (b – rd)²/(r + s)

C.            ½ × (b + rd)²/(r – s)

D.            (b – rd)²/(s – r)

Answer: (b – rd)²/(r – s)