The area of a sloping surface of a protective embankment of mean height d, side slopes S : 1 and length L is _____.

A

$$ d \times d \times s $$

B

$$\surd[(d_{2} \times ds_{2})]$$

C

$$L.D \surd(1+s_{2})$$

D

$$ 2 Ld \surd(1+s_{2})$$