Assertion: A direction current flows through a metallic rod, producing a magnetic field only outside the rod.
Reason: There is no flow of charge carriers inside the rod.

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, but R is true.