Assertion (A): When we connect a resistor to a battery, the flow of current starts almost instantaneously when switch is put on.
Reason(B): The random motion of electron take place with a speed of the order of  ${10}^{6}m/s$.
A) A is correct, B is correct B is a correct explanation for A
B) A is correct, B is correct B is NOT a correct explanation for A
C) A is correct, B is not correct
D) A is not correct, B is correct