Answer: I & II
Explanation: gauss law states that the total amount of electric flux through a closed surface equals the net electric charge enclose divided by permittivity of free space.
Φ = ∫E. dA = Q/ε0
Φ = electric flux
ε0 = permittivity of free space
E= strength of electric field.
dA = fraction of area that flux passes through.
Q = net charge enclosed.
Hence a zero net flux is only possible when the net charge is equals to zero and when there is no charge in the enclosed surface.
