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 believe your answer is d)

lee and grant, both of whom held the highest rank in their respective armies, had known each other slightly during the mexican-american war (1846-48) and began their dialogue by exchanging awkward personal inquiries. characteristically, grant had arrived in his mud-splattered field uniform while lee had turned out in full dress attire, complete with sash and sword.

explanation: