Vagus
Let's look at the list of cranial nerves to see what they do
0. Terminal - Animal tests indicate this nerve is involved in detecting pheromones.
I. Olfactory - Handles the sense of smell.
II. Optic - Handles the transmission of visual signals.
III. Oculomotor - Handles the movement of your eyes.
IV. Trochlear - More eye movement.
V. Trigeminal - Allows you to sense touch on your face and chew your food.
VI. Abducens - More involvement with the eyes.
VII. Facial - The name says it all.
VIII. Vestibulocochlear - Sense of hearing and balance using the inner ear.
IX. Glossopharyngeal - Taste and some motor movement.
X. Vagus - This one innervates nearly all of the thoracic and abdominal viscera. And that pretty much defines the question. So this is the nerve to choose.
XI. Accessory - Handles a few muscles.
XII. Hypoglossal - Handles a long of the tongue movement.
