The value of electric potential at any point due to an electric dipole is:

• A
  $k \cdot \frac{{\vec p \times \vec r}}{{{r^2}}}$
• B
  $k \cdot \frac{{\vec p \times \vec r}}{{{r^3}}}$
• C
  $k \cdot \frac{{\vec p \cdot \vec r}}{{{r^2}}}$
• D
  $k \cdot \frac{{\vec p \cdot \vec r}}{{{r^3}}}$