B because this was the most unesscary thing EVER
an explanatory essay tries to explain a concept, or problem without trying to discredit or mention another writing piece, or article. an argumentative essay takes an article or piece of writing and has detailed facts, or reasons as to why that article is wrong.
If you look at the years of the states and write down the ones in 1889 and 1900, it gets easier. Three that I got were Wshington, Montana, and South Dakota (I'm sure there are more but those were three).
b.must be the correct answer