A student measured the length of a rod and wrote it as 3.50 cm .Which instrument did he use to measure it ?

Question

(a) A meter scale(b) A vernier calliper where the 10 divisions in vernier scale matches with 9 division in main scale and main scale has 10 divisions in 1 cm .(c) A screw gauge having 100 divisions in the circular scale and pitch as 1 mm .(d) A screw gauge having 50 divisions in the circular scale and pitch as 1 mm .