Step 1: Torque formula.
The torque \( \tau \) on a magnetic moment \( \mathbf{m} \) in a magnetic field \( \mathbf{B} \) is given by the cross product:
\[
\tau = \mathbf{m} \times \mathbf{B}
\]
This represents the force that causes rotational motion.
Thus, the correct answer is (2).