A Loop of Current-Carrying Wire Has a Magnetic Dipole Moment

Multiple Choice

A loop of current-carrying wire has a magnetic dipole moment of 5 * 10^-4 A . m². The moment initially is aligned with a 0.5-T magnetic filed.To rotate the loop so its dipole momentt is perpendicular to the field and hold it in that orentation, you must do work of:

A) 0
B) 2.5* 10^-4 J
C) -2.5 * 10^-4 J
D) 1.0 * 10^-3 J
E) -1.0 * 10^-3 J