Units , Dimensions and Error Analysis

In an experiment to find out the diameter of wire using screw gauge, the following observations were noted : (A) Screw moves 0.5 \mathrm{~mm} on main scale in one complete rotation (B) Total divisions on circular scale =50 (C) Main scale reading is 2.5 \mathrm{~mm} (D) 45^{\text {th }} division of circular scale is in the pitch line (E) Instrument has 0.03 mm negative error Then the diameter of wire is :