They're trying to block a law that will send a mail-in ballot to every voter.
Many are expected to vote by mail.
The idea was immediately rejected by Democrats and Republicans
Trump said the last five questions on the test were "very hard". One of them was 'count back from 100 by 7'.
He has criticised Trump for not reading intelligence briefings.
"I think West, or anyone else, has missed their window of opportunity to have a meaningful impact."
Trump was sitting at 36 percent and Biden 50, nearly four months out from election day.
Trump retorted calling Powell "a real stiff".
Obama endorsed him two weeks ago.