Why did the united states go to war with mexico in 1846?

Which of the following is the correct order of key events in the sioux conflicts? (1) red cloud’s war (2) treaty of fort laramie (3) black hills gold rush (4) battle of little bighorn (1) treaty of fort laramie (2) battle of little bighorn (3) red cloud’s war (4) black hills gold rush (1) black hills gold rush (2) red cloud’s war (3) battle of little bighorn (4) treaty of fort laramie (1) battle of little bighorn (2) treaty of fort laramie (3) black hills gold rush (4) red cloud’s war