word order - Where does the verb go on this question? Is it even a reported question?

I understand that when I report a question, I put the subject back in front of the verb, as in: "He asked if she was going to be late."

But I always get puzzled when it comes to reporting a question with a question. (In fact I'm not even sure this is reported speech, but I think it is, because I'm reporting my own doubts.)

My starting point is the question:

What is the task for the afternoon class?

But now I want to ask if anyone in a group knows what the task is. Which of the following alternatives would be grammatical?

(a) Does anyone know what is the task for the afternoon class?
(b) Does anyone know what the task is for the afternoon class?
(c) Does anyone know what the task for the afternoon class is?

Intuitively, I would pick (c), but I don't know if that is the correct choice, and I certainly don't know why.

Can anyone tell me which of the options is correct and why?