In finding the electric field using Gauss's Law,the formula $|\overrightarrow{E}| = \frac{q_{enc}}{\varepsilon_{0}|A|}$ is applicable. In the formula,$\varepsilon_{0}$ is the permittivity of free space,$A$ is the area of the Gaussian surface,and $q_{enc}$ is the charge enclosed by the Gaussian surface. The equation can be used in which of the following situations?

• A
  Only when the Gaussian surface is an equipotential surface.
• B
  Only when $|\overrightarrow{E}|$ is constant on the surface.
• C
  For any choice of Gaussian surface.
• D
  Only when the Gaussian surface is an equipotential surface and $|\overrightarrow{E}|$ is constant on the surface.