I agree that racism is a spectrum, spanning anywhere from microagressions that contribute to systemic racism, to overt dismissals of human rights. Generally, the term "racist" is used to mean "exists further than X on the scale of racism". Whether or not somebody is racist by virtue solely of voting for a blatantly racist candidate is a matter of discussion for where that line of X is, and is covered under my comment about option (C).
This also gets into the point where racism will continue to exist so long as "not racist" is seen as one end of the spectrum. Rather, in order to be appropriately egalitarian, one must be anti-racist wherever society is racist.
