I vote all of the above; none of them are mutually exclusive. But he does appear to be hiding things.
That whole audit excuse is bogus, as the head of the IRA came out and said this week. Also, the head of the IRS made it clear that the only reason anyone is audited that many years are highly suspicious tax returns.
An anonymous GOP donor offered $5 million to charity if Trump would release his tax returns -- which mirrors Trump's birther offer to the president. Wonder how it feels to be on the other side of that offer?