A student measured the length of a rod and wrote it as `3.50cm`. Which insturment did he use to measure it?
A. A screw gauge having `100` divisions in the circular scale and pitch as `1 mm`
B. A screw gauge having `50` divisions in the circular scale and pitch as `1 mm`
C. A metre scale
D. A vernier callipers where the `10` divisions in vernier scale matches with `9` divisions in main scale and main scale has `10` divisions in `1cm`.
