how Vietnam’s political boundaries, affiliations, and alliances changed from the end of World War II to 1975

Well that's a complicated mess. During WWII the Viet Minh assisted the US army by recovering downed pilots. The same day that the US was signing the peace agreements with Japan H• Chi Minh declared Vietnam an independent country. Uncle H• was said to have quoted excerpts from the US Declaration of Independence in attempts to gain support from the US. Almost immediately following their Declaration of Independence the French intervened and attempted to gain their former colonial rule over Vietnam once again. This sparked the 1st Indochina war against the French and the Viet Minh.

A,) cause a & b are equal & both gives 180°