A Tightly Wound Solenoid Is 15 Cm Long,has 350 Turns,carries $\chi$

Multiple Choice

A tightly wound solenoid is 15 cm long,has 350 turns,carries a current of 3.0 A,and has an aluminum core ( $\chi$ _m = 2.3 $\times$ 10^-5) .If you ignore end effects,you will find that the value of at the center is approximately

A) 11 mT
B) 8.8 mT
C) 1.8 mT
D) 7.0 mT
E) 6.2 mT