Point charges are placed at the vertices of a regular hexagon with center $O$ and side length $L$ as shown in the figure. Given $K = \frac{q}{4\pi \epsilon_0 L^2}$,which of the following statements is correct?

• A
  The electric field at $O$ is $6K$.
• B
  The electric potential at point $O$ is zero.
• C
  The potential at all points on the line $OD$ is the same.
• D
  The potential at all points on the line $ST$ is the same.