B) Preventing the spread of communism
The role of the united state in Vietnam war began after the world warII. US mission was to restrict the communist domination that was present in Vietnam government, this was because communism could easily spread to the Neighbouring countries which would result to a change in the balance of power throughout Southeast Asia.
Ohh i know this The wall is covered with Byzantine mosaic designs.
Salvador Dalí is the painter
The word you might be looking for is "surrender"