Vernier Callipers Questions

Consider the diameter of a spherical object being measured with the help of a Vernier callipers. Suppose its $10$ Vernier Scale Divisions (V.S.D.) are equal to its $9$ Main Scale Divisions (M.S.D.). The least division in the M.S. is $0.1\text{cm}$ and the zero of V.S. is at $x=0.1\text{cm}$ when the jaws of Vernier callipers are closed.
If the main scale reading for the diameter is $M=5\text{cm}$ and the number of coinciding vernier division is $8$, the measured diameter after zero error correction, is: