Step 1: Understanding the Concept
Cranial nerves are numbered from front to back.
Step 2: Recall the order
I olfactory, II optic, III oculomotor, IV trochlear, V trigeminal, VI abducens, VII facial, X vagus.
Step 3: Conclusion
The third nerve is the oculomotor nerve, which moves most eyeball muscles.
Final Answer:
Cranial nerve III is the oculomotor nerve.
\[ \boxed{\text{(C) }\text{Oculomotor}} \]