Which of the following was the reason the U.S. went to war with Mexico in 1846?

A) to set boundary of the Mexico border at the Rio Grande River
B) to make Northern abolitionists happy
C) to gain more territory from Mexico, including California
D) to help President Polk keep his campaign promises

C) to gain more territory from Mexico, including California

Well pick one bot.

All of the above reasons were factors that contributed to the U.S. going to war with Mexico in 1846.