State Gauss's Theorem in Electrostatics:
a) "The electric field inside a closed surface is proportional to the total charge enclosed by the surface."
b) "The electric flux through any closed surface is equal to 1/ε₀​​ times the total charge enclosed by the surface."
c) "The electric potential on a closed surface is directly proportional to the total charge enclosed by the surface."
d) "The electric field lines inside a closed surface are always perpendicular to the surface."