Vernier calipers having 1 main scale division as 0.1 cm is designed to have a least count of 0.02 cm. If n be the number of divisions on vernier scale and m be the length of vernier scale, then:
A n=10,m=0.5 cm
B n=9,m=0.4 cm
C n=10,m=0.8 cm
D n=10,m=0.2 cm
