Final answer:
The Hypoglossal nerve (option d) is responsible for controlling the muscles of the tongue, and it is the cranial nerve being tested when Tomasina is asked to stick out her tongue.
Step-by-step explanation:
The cranial nerve being tested when Tomasina was asked to stick out her tongue is the Hypoglossal nerve (option d). The Hypoglossal nerve is responsible for controlling the muscles of the tongue, except for the palatoglossus muscle which is controlled by the vagus nerve. The test for Hypoglossal function is the "stick out your tongue" part of the examination.