Which event marked the end of the vietnam war? north vietnamese forces returned american pows. us troops withdrew from vietnam. south vietnam surrendered after saigon fell. the united states reduced its involvement in vietnam.

The Answer is

South Vietnam surrendered after Saigon fell.

b

explanation:

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.