Look:
In the cartoon the sentence “It’s a beautiful day, isn’t it?” the “isn’t it?” is a Tag Question. According to Cambridge dictionary, a tag question is “a short phrase added to the end of a sentence to check information, or to ask if someone agrees with you”.
(https://dictionary.cambridge.org/dictionary/english/tag-question).
Choose from the alternatives below, the tag question that uses an incorrect auxiliary verb form:
