Ten electrons are equally spaced and fixed around a circle of radius R. Relative to V = 0 at infinity, the electrostatic potential V and the electric field E at the centre C are 

• A

  $\mathrm{V}\ne 0\text{ and }\overrightarrow{\mathrm{E}}\ne 0$

• B

  $\mathrm{V}\ne 0\text{ and }\overrightarrow{\mathrm{E}}=0$

• C

  $\mathrm{V}=0\text{ and }\overrightarrow{\mathrm{E}}=0$

• D

  $\mathrm{V}=0\text{ and }\overrightarrow{\mathrm{E}}\ne 0$