Assertion- In the absence of an external electric field, the dipole moment per unit volume of a polar dielectric is zero.
Reason- The dipoles of a polar dielectric are randomly oriented.
A) Both A and R are true and R is the correct explanation of A
B) Both A and R are true but R is not the correct explanation of A.
C) A is true but R is false.
D) A is false and R is also false.