Respuesta :
I'm thinking that either "Me va excelente." or "Estoy bien." would be acceptable in an informal conversation. But if it is for a Spanish course, I'll go with "Me va excelente." Hope it helps!
Answer:
Me va excelente
Explanation:
In the conversation, we know one of the characters is a Professor and the other one is likely a student. So the conversation likely has a more formal tone, which is why "me va excelente" completes it better than "estoy bien". The other options are greetings that don't answer the question being asked so they can't be correct.