Answer:
C. The dancers, mentrers of Ms. Contreras's class, leaped and twirled through the audience.
Step-by-step explanation:
An appositive is a noun phrase that is included in a sentence thereby renaming the noun right next to it. This means that the sentence can also be deemed a valid full sentence with the appositive noun.
In the given original sentence, there is no appositive. And among the given options, sentence C has an appositive which is "members of Ms. Contreras's class". And this appositive phrase modifies or add to the already existing noun "dancers".
Thus, the correct answer is option C.