A. The Spanish-American War can be seen as a humanitarian effort because the US is trying to help Cuba get rid of a Spanish government that severely limited the rights of their citizens and treated them cruel for an extended period of time.
B. The US involvement in the Spanish-American War was also driven by imperialist motives, as the treaty that ends the war resulted in the US gaining the territories of Guam and Puerto Rico.
C. The Spanish-American War can be seen as the beginning of the era of imperialism. This is because shortly after this war, the US will go on to annex other territories such as the Philippines and Hawaii.