Diameter of a steel ball is measured using a Vernier callipers 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 : If the zero error is 20.03 cm, then mean corrected diameter is :

Question

$\begin{array}{1 1} 0.56\;cm \\ 0.59\;cm \\ 0.53\;cm \\ 0.52 \;cm \end{array}$