Final answer:
The correct answer is 'are,' making the full sentence 'The kids are dancing to the music.' It uses the present continuous tense, which is appropriate for actions currently in progress and with plural subjects.
Step-by-step explanation:
The correct answer to fill in the blank in the sentence "The kids ______ dancing to the music." is 'are.' Therefore, the complete sentence should read: The kids are dancing to the music. This sentence requires the use of the present continuous tense to describe an action that is currently in progress. The subject 'kids' is a plural noun, which means the correct verb conjugation to use is 'are.' The present continuous tense is formed with the subject plus the appropriate form of the verb 'to be' (am/is/are) and the -ing form of the main verb (dancing in this case).