A fundamental equation of void ratio (e), specific gravity (G), water content (W) and the degree of saturation $$ (S_p) $$ is

A

$$ e = \frac{WG}{S_p} $$

B

$$ W = \frac{eG}{S_p} $$

C

$$ G = \frac{eW}{S_p} $$

D

$$ S_p = \frac{eW}{G} $$