Positive Charge Q Is Placed on a Conducting Spherical Shell $\pi$

Multiple Choice

Positive charge Q is placed on a conducting spherical shell with inner radius R₁ and outer radius R₂. A particle with charge q is placed at the center of the cavity. The magnitude of the electric field at a point in the cavity, a distance r from the center, is:

A)
B)
C) q/4 $\pi$$\varepsilon$ ₀r²
D) (q + Q) /4 $\pi$$\varepsilon$ ₀r²
E)