Which of the Following Is an Accurate Statement

Multiple Choice

Which of the following is an accurate statement?

A) Magnetic field lines have as their sources north and south poles.
B) A magnetic field line is,by definition,tangent to the direction of the magnetic force on a moving charge at a given point in space.
C) The magnetic force on a moving charge does not change its energy.
D) The magnetic force on a current-carrying wire is greatest when the wire is parallel to the magnetic field.
E) A current-carrying loop of wire tends to line up with its plane parallel to an external magnetic field in which it is positioned.