Ten charges are placed on the circumference of a circle of radius R with constant angular separation between successive charges. Alternate charges 1,3, 5,7,9 have charge (+q) each, while 2,4,6,8,10 have charge (-q) each. The potential V and the electric field E at the centre of the circle are respectively.  (Take V = 0 at infinity)

• A

  $V=\frac{10q}{4\pi {\in }_{0}R};E=0$

• B

  $V=0;E=0$

• C

  $V=\frac{10q}{4\pi {\in }_{0}R};E=\frac{10q}{4\pi {\in }_0{R}^2}$

• D

  $V=0;E=\frac{10q}{4\pi {\in }_0{R}^2}$