$A$ positive charge $q$ is kept at the center of a thick shell of inner radius $R_1$ and outer radius $R_2$ which is made up of conducting material. If $\phi_1$ is the flux through a closed Gaussian surface $S_1$ whose radius is just less than $R_1$ and $\phi_2$ is the flux through a closed Gaussian surface $S_2$ whose radius is just greater than $R_1$,then:

• A
  $\phi_1 > \phi_2$
• B
  $\phi_2 > \phi_1$
• C
  $\phi_1 = \phi_2 = \frac{q}{\varepsilon_0}$
• D
  $\phi_1 = \phi_2 = 0$