Which of these contributes most to the problem of air pollution? A. burning gasoline in cars
B. shipping oil around the world
C. storing oil in large tanks
D. drilling for oil in the desert regions

I believe its A

if I'm wrong I will delete this.

Explanation:

the answer is

a) revise existing treaties

b) do away with political alliances

c) prevent the spread of communism

d) bring an end to european colonization

the main goal of the southeast asia treaty organization was to prevent the spread of communism in southeast asia.