A Solenoid Is Wound with 970 Turns on a Form

A solenoid is wound with 970 turns on a form 4.0 cm in diameter and 50 cm long. The windings carry a current I in the sense that is shown in the figure. The current produces a magnetic field, of magnitude 4.3 mT, near the center of the solenoid. Find the current in the solenoid windings. (μ₀ = 4π × 10^-7 T ∙ m/A)

A) 1.8 A
B) 1.5 A
C) 1.3 A
D) 2.2 A
E) 2.0 A