Step 1: Understanding the units of magnetism.
Magnetism is fundamentally characterized by the presence of dipoles, not just isolated poles. The magnetic dipole is the basic unit of magnetism that consists of two opposite poles, north and south, which always appear together in a magnet. It is impossible to isolate a single north or south pole in nature, as every magnet is a dipole by nature.
Step 2: Conclusion.
Thus, the ultimate individual unit of magnetism is the magnetic dipole, corresponding to option (C).