How many cranial nerves are known to have both sensory and motor functions?

The correct choice reflects that there are four cranial nerves known to have both sensory and motor functions. These nerves are unique because they are responsible for transmitting sensory information to the brain as well as controlling muscle movements. The cranial nerves that fulfill both roles are the trigeminal nerve, facial nerve, glossopharyngeal nerve, and the vagus nerve.

Understanding the functions of these cranial nerves is essential, as they play critical roles in sensory perception (such as taste and sensation) and coordination of certain voluntary movements and autonomic functions. Recognizing this combination of functions helps in comprehending how the cranial nerves contribute to complex physiological processes in the human body.

Other options indicating three, six, or five cranial nerves confuse the classification of the cranial nerves, as they do not account for the complete list of those with both sensory and motor capabilities, which is established as four.