Which cranial nerve is responsible for the sense of smell?

Cranial nerve I, also known as the olfactory nerve, is specifically responsible for the sense of smell. It functions by transmitting sensory information from the olfactory receptors in the nasal cavity to the olfactory bulb, which processes the signals and connects them to higher brain regions involved in smell perception.

Cranial nerve II, or the optic nerve, is associated with vision rather than olfactory senses. Cranial nerve V, the trigeminal nerve, primarily carries sensory information from the face and is involved in sensations such as touch and pain rather than smell. Lastly, cranial nerve VIII, known as the vestibulocochlear nerve, is concerned with hearing and balance, making it unrelated to the sense of smell. Thus, the correct answer focuses entirely on the olfactory function provided by cranial nerve I.