a)the man on the right is known as a "dove" or a hippie; peace maker and represents the people who wanted to end the Vietnam war because of how gruesome it was.
b)The man sitting in the chair represents most politicians and their stance on the war aggressive twords the "doves"
c)this man represents the victims of the war and napalm strike
d)Napalm is a flammable liquid used in warfare, a mix of a gelling agent and gasoline, it sticks to the skin and causes severe burns.
This is the best I know from it and remember, but i'm not sure what book you have