The correct answer is C. Remain
Step-by-step explanation:
In grammar, a linking verb is a type of verb that connects the subject and the predicate defining the subject through this relationship. Common linking verbs include become, seem, appear, taste, and remain. These verbs differ form action verbs because action verbs express actions performed by the subject. According to this, in the case of the sentence "We learned that Native American and Hispanic cultures remain influential in New Mexico" the linking verb is "remain" because this word links the subject "Native American and Hispanic cultures" and the predicate "influential in New Mexico" and in this way defines the subject. Also, this word does not express explicitly an action.