B

The magnetic dipole moment is a vector quantity that represents the strength and direction of a magnetic source.
Step 1: By definition, a vector quantity has both magnitude and direction, whereas a scalar quantity only has magnitude.
Step 2: The magnetic dipole moment is represented mathematically as \( \vec{m} = I \cdot \vec{A} \), where \( I \) is the current and \( \vec{A} \) is the area vector perpendicular to the plane of the loop.
Step 3: Since it has a specific direction associated with it (pointing from the south magnetic pole to the north magnetic pole), it confirms it is a vector quantity.
Therefore, the correct answer is option B.