A conductor having a cavity is given a positive charge. What are field strengths $E_A,E_B$ and $E_C$ at point A (inside the cavity), B (with in conductor but outside cavity ) and C (outside the conductor ) respectively ?

Question

$(A)\;E_A \neq 0, E_B \neq 0 , E_C \neq 0 \\ (B)\;E_A \neq 0, E_B = 0 , E_C \neq 0 \\ (C)\; E_A = 0, E_B = 0 , E_C \neq 0 \\ (D)\;None $