A screw gauge has 50 divisions on its circular scale. The circular scale is 4 units ahead of the pitch scale marking , prior to use. Upon one complete rotation of the circular scale, a displacement of 0.5 mm is noticed on the pitch scale . The nature of zero error involved , and the least count of the screw gauge, are respectively.

Options

A. Negative , 2 `mu `m
B. Positive , 10 `mu ` m
C. Positive , `0.1 mm`
D. Positive , 0.1 `mu ` m