Was/were established to settle disputes between the states.
a. the state department
b. central courts
c. the executive branch
d. the presidency

Central courts were established to settle disputes between the states. The correct option among all the options that are given in the question is the second option or option "B". To be more specific, it can be said that the Supreme court is the court that has the power to settle disputes between the states.

Democracy and darwinism would be my answer.