Which statement best summarizes the United States policy in Latin
America in the 20th century? *
A. The "Big Stick" policy was repealed.
B. The main goals of the US has been to bring about the unification of Latin American nations
C. The United States has actively supported European involvement in Latin American affairs.
D. The US has intervened in Latin American Affairs when US self-interest has been involved

D. The US has intervened in Latin American Affairs when US self-interest has been involved

Explanation:

In the 20th century, US policy towards Latin America shifted from the Monroe doctrine that demanded that European powers not attempt to colonize any more Latin American states to a policy that demanded that US interests be protected in Latin America. Under President T. Roosevelt, the US decided that they would expand it's commercial interests into Latin America to enable it to control and protect the continent further as well as to assert it's will.

For instance, when in 1903, Columbia refused to grant US permission to build the Pans Canal, the US reacted by supporting Panamanian rebels through back channels and preventing Columbia from retaking Panama when the latter declared independence. The Panamanian government then responded in gratitude by allowing a canal to be built.

Another instance was the Mexican Revolutions occuring from 1910 to 1920 where the US would support any new Mexican government so long as they abided by US foreign policy.

b) a state law could be declared illegal if it contradicted the constitution.

explanation:

the conflict of this case originated when james w. mcculloch, a cashier of the baltimore branch of the second bank of the united states that the congress had chartered in 1816, refused to pay a tax imposed by the maryland state.

in the case, the state of maryland appealed that the establishment of a second bank was unconstitutional since the constitution didn't say anything about granting that power to congress. however, the case determined that even if such right wasn't specifically stated in the constitution, it was part of the "implied powers" of the government enunciated in article i, section 8.

the case also eliminated maryland's legislation to impose taxes to a national bank, asserting that even though the states retained the power of taxation, the constitution's laws are supreme and can not be controlled by the states, therefore, if a state law contradicts the constitution, it should be declared illegal.

explanation:

silk

indigo  

rice

all the other answers are wrong