Answer:
B
Explanation:
The answer is B because first of all Russia is one of the most spoken languages, but it has nothing to do with the narrative. Same thing goes to option D. This leaves us with only two options B and C. C could be an answer, but option B will fit into the narrative better.
The origins and cause of the Mexican-American War are very complex, but in general it was started only because the US under President Polk wanted more land.