(3) is kind of a strawman. No one actually thinks Donald Trump said the virus itself is a hoax. In context the "hoax" is referring to the claims about the seriousness of the virus and the government response to it.

And there are definitely Trump supporters calling the situation a hoax, as in, "this is a hoax to blow up the stock market and make Trump look bad, don't you know that more people die of the flu every year?".