Keeping the instrument height as 1½ m, length of staff 4 m, the up gradient of the ground 1 in 10, the sight on the up slope must be less than

Keeping the instrument height as 1½ m, length of staff 4 m, the up gr

1.	Keeping the instrument height as 1½ m, length of staff 4 m, the up gradient of the ground 1 in 10, the sight on the up slope must be less than
A.	25 cm
B.	20 m
C.	45 m
D.	10 m
Answer» D. 10 m