The longest river in the United States is the River.

A. Ohio
B. Missouri
C. Colorado
D. Mississippi

B should be your answer.

The Missouri river is the longest river in the U.S.

Explanation: Rising in the Rocky Mountains of western Montana, the Missouri flows east and south for 2,341 miles (3,767 km) before entering the Mississippi River north of St. Louis, Missouri.

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.

credit card number 4 is the right answer