Answer:
The right option that could fill the blank is:
- ¿A <u>qué</u> hora es la clase?
Explanation:
The words <em>"qué"</em> and <em>"cuál"</em> have two very marked uses that can be taken into account when selecting them within a sentence, <em>"cuál"</em> or its plural <em>"cuáles"</em> is usually used when selecting an option from a <u>homogeneous group</u>, for example, the seller of an ice cream shop wants to know the flavor of ice cream that the buyer wants, therefore, in Spanish he would ask the question with "<em>cuál"</em> and it is called the homogeneous group since all are flavors, in the case of the hour is not so, since although all are hours, the option is <u>undetermined</u>, that is, a <u>heterogeneous group</u>, therefore, the word that is usually used to ask for the time is <u>"qué"</u>.