Final answer:
The three nouns in the sentence are 'Mrs. Wynn', 'class', and 'test', with 'Mrs. Wynn' being the subject, 'class' the indirect object, and 'test' the object of the preposition.
Step-by-step explanation:
The three nouns in the sentence 'Mrs. Wynn asked the class to study for the test.' are Mrs. Wynn, class, and test. Mrs. Wynn is a proper noun and the subject of the sentence; class is a common noun serving as the indirect object of the verb 'asked'; and test is another common noun, which is the object of the preposition 'for.' These nouns are key parts of sentence structure, helping to identify who is doing an action, to whom the action is directed, and what the action pertains to.