I think that one because if you look on the acid vs base chart acid is from 0-6 and bases are from 8-14 and acids are less toxic, so you would infer that lake A has acid and lake B has bases.
i would have picked the ones closest to 7 ,which is neutral, but I'm not sure that a base can be lower then 7 so I didn't pick answer C
the process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth.
