Solenoids: Consider a Solenoid of Length L, N Windings, and Radius

Multiple Choice

Solenoids: Consider a solenoid of length L, N windings, and radius b (L is much longer than b) . A current I is flowing through the wire. If the length of the solenoid became twice as long (2L) , and all other quantities remained the same, the magnetic field inside the solenoid would

A) remain the same.
B) become twice as strong.
C) become one half as strong.