JEE Main 2015 Physics question

Diameter of a steel ball is measured using a Vernier calipers which has divisions of 0.1 cm on its main scale (MS) and 10 divisions of its Vernier scale (VS) match 9 divisions on the main scale. Three such measurements for a ball are given as: S.No. 1: MS = 0.5 cm, VS divisions = 8; S.No. 2: MS = 0.5 cm, VS divisions = 4; S.No. 3: MS = 0.5 cm, VS divisions = 6. If the zero error is cm, then mean corrected diameter is:

• (1)0.53 cm
• (2)0.56 cm
• (3)0.59 cmCorrect
• (4)0.52 cm