Indication post for detonator should be provided at a distance of ---------meter and --------- meter for BG level crossing
a) 400 meters in 800 meters
b) 500 meters and 1200 meters
c) 600 meters and 1200 meter *
d)600 meters and 1000 meters
a) 400 meters in 800 meters
b) 500 meters and 1200 meters
c) 600 meters and 1200 meter *
d)600 meters and 1000 meters