Which is correct: None of you have/has answered the question correctly.

Both are correct. The word ‘none’ is actually from ‘not one’. Based on this, people have argued that when ‘none of’ precedes a plural noun, the verb that follows it must be singular. Nowadays, it is okay to use either a singular or a plural verb with ‘none of’. In formal contexts, the British prefer a singular verb. The Americans, on the other hand, mostly use a plural verb after ‘none of’.

*None of my father’s articles have/has been published in that journal.