The formation width of a highway with no transverse slope on an embankmentis B. The height of the embankment is d and side slope of the embankmentis S: 1, The area of cross
section of the embankment is

A

$$B + d + Sd$$

B

$$B * d + Sd$$

C

$$B * d + sd^{2}$$

D

$$\frac{1}{2} (B * d + Sd^{2})$$