The actual war between the United States and
Mexico started after

( the United States sent troops into the disputed border region.

( Mexican forces attacked and killed American troops.

i think that the answer is polishing peanuts

the fact that could also be added to column b is that during world war ii, specifically between the years 1941 and 1945, japan expanded its territory towards the indonesian territory in what was known later as part of the "pacific war". in that time, japan could conquer the philipines, singapore,   borneo, central java, malang, cebu, sumatra and various other islands of the area, therefore expanding its territory for a brief period of time.