The major purpose of the monroe doctrine (1823) was to

Monroe's 1823 message to Congress had the Monroe Doctrine. It warned European powers not to come between the affairs of the Western Hemisphere. The U.S. has always taken an interest in its neighbors – the nations of the Western Hemisphere.

the article must be ratified by three-fourths (38) of states within a proscribed deadline.

source:

the answer your looking for is c. : )