People traveling to foreign countries are often advised to boil their water before they drink it. Boiling kills any parasites in the water. Both protists and bacteria can be transmitted by drinking unclean water. (Please answer if you know)
How are protist and bacteria cells different?

A. Bacteria are prokaryotes but protists are eukaryotes.
B. Bacteria always have cells walls but protists never have cell walls.
C. Bacteria are multicellular but protists are unicellular.
D. Bacteria cells have nuclei but protists cells lack nuclei.