Answer:
Could be either A or C depending on what they're asking. A is asking if the person wants them to list them into ballet and C is asking if the person already listed themselves for the ballet class.
Explanation:
Yo (nunca) estudiaba con Mariela porque no la conocía bien.
<span>Él es un compañero de clase is the right answer. The 1st sentence is ella but </span>compañero should be compañera. In the second one ella should not have an accent mark and in the last one el doesn't match with una.