The best answer is A.
In 1903, the United States supported a rebel group from Panama which was then part of Colombia.
The US signed a treaty with Colombia called the Hay - Herran treaty which granted the USA use of the canal on its completion.
The Colombian government refused to sign for fear of losing sovereignty and the US responded by approving a rebellion by Panama nationalists which started on November 1903.
The US sent a battle ship to Panama to " protect American lives" in Panama making Colombian forces afraid to sail to Panama to quell the rebellion. The rebellion succeeded and Panama declared itself independent from Colombia.
