For heavy embankments and dams, of height h, the depth of exploration of soil should not be less than$?

For heavy embankments and dams, of height h, the depth of exploration

1.	For heavy embankments and dams, of height h, the depth of exploration of soil should not be less than$?
A.	h/4
B.	1/2 h
C.	h
D.	2 h
Answer» E.