I know that they adopted the Egyptian religious practices, sooooo your answer is D.(^○^)
It is like Nixon said, "no event in American history is more misunderstood than the Vietnam War." I can't give a clear answer but I do have some food for thought which may paint a big picture.
1. You have to keep in mind that Vietnam was not about who killed more troops.
If the winner of the Vietnam war was declared by who killed more troops than the U.S. would win hands down. The U.S. casualties were roughly half a million, where as the Vietcong suffered a little more than a million. Then how did we lose?
2. Keep in mind that at this time technology has improved and Vietnam is the first war where people are watching it go on right at home on there television screen.
They are seeing their sons being shot and viewing dead soldiers every single day.
You did not see this in WW1 or WW2 or the Korena War.
It is not used exclusively for that platform
Topographic map to find the elevation of an area