<em>If a student would like to be part of the class play, </em><em>C. he or she should come to the drama room this afternoon.</em>
Explanation:
Option <em>C. he or she should come to the drama room this afternoon</em> is the correct option, because it is the only sentence that provides the appropriate subject to make reference to the antecedent "a student." "A student" refers to a singular, 3rd person subject, and the only sentence that provides that option is "he or she..."