The Civil War was fought in 1861, so the answer would be D: 1800.
The only conjunction in this sentence is C) but.
All of the other options are prepositions, not conjunctions.
<span>The most important reason the Indo-Euorpean languages dominate the globe geographically today is that B. European colonization around the world helped spread the languages. Throughout most of the world, except for Africa, Indo-European languages are spoken even today. Such languages are English, Spanish, Russian, Hindi, etc. </span>