If P is the vertical relation and ρ is the vertical deflection, then the modulus of sub-grade reaction is _______

If P is the vertical relation and ρ is the vertical deflection, then

1.	If P is the vertical relation and ρ is the vertical deflection, then the modulus of sub-grade reaction is _______
A.	\(k_s=\frac{P}{ρ}\)
B.	\(k_s=\frac{1}{P}\)
C.	\(k_s=\frac{ρ}{P}\)
D.	\(k_s=\frac{P}{2ρ}\)
Answer» B. \(k_s=\frac{1}{P}\)