The second and third examples are both correct. Which one is grammatically correct or better? I have two assignments, one of which is done.
How to Order a Custom Guitar from Belltone, Gibson, Kiesel, and Fender
It is possible that the singular/plural choice is not a purely syntactical matter, but partially depends on whether the speaker's focus. Which one is the best is obviously a question format, so it makes sense that which one the best is should be the correct form. I have two assignments, one of them is done.
The first example is incorrect.
Which one you use is mostly a matter of preference, although a hundred.
