Double question

[Pierce111]

In case of double question, which form is correct:
a) What do you think, where does it come form?
or
b) What do you think, where it comes form?
?

 

[5jj]

You have two questions there - What do you think? Where does it come from?

You can combine the ideas if you wish - Where do you think it comes from? Where does it come from, do you think? What do you think about where it comes from?