What are the three provided options for what caused the Black Death?

The black death came from fleas. Rats in China had these fleas, and they found their way to Europe. The black death spread so easily because a) there was no proper hygiene, b) cities were often crowded and animals would walk around the streets with humans, c) the 'treatments' that doctors had really didn't have anything to do with the black death. In the end, the black death ended up killing 1/3 of Europe's population and was actually one of the reasons why the feudal system ended.

I know that during the enlightenment Benjamin Franklin was a scientist and he discovered electricity then he told people and Thomas Paine was a radical propagandist for the American revolution and he used enlightenment ideals to argue against the colonies for revolting against taxation but not independence.