Why did president bush send u. s. troops into panama in december 1989?

a. he wanted to gain control of the panama canal and stop drug trafficking.

b. the panama president refused to stop refugees leaving for the u. s. border.

c. the panama government was in danger of being overthrown by its prior dictator, and the u. s. went in to make sure the new president took power and the prior dictator was brought to justice.

d. none of the above.