Five point charges, +q each, are placed at the five vertices of a regular hexagon. The distance of the center of the hexagon from any of the vertices is a. The electric field at the center of the hexagon is

• A

  $\frac{q}{4\pi {\epsilon }_0{a}^2}$

• B

  $\frac{q}{8\pi {\epsilon }_0{a}^2}$

• C

  $\frac{q}{16\pi {\epsilon }_0{a}^2}$

• D

  zero