In a conductor which of the following relations hold good?

A)
∇ . D = r
B)
∇ x D = r
C)
∇ x D = 0
D)
∇ . D = 0

Correct Answer : Option (C) :   ∇ x D = 0


Explanation : Inside a conductor free charge is zero, hence, ∇ x D = 0.