Which Is One of the Reasons That Power and Responsibility

Which is one of the reasons that power and responsibility of the presidency has grown?

A) The presidents' use of the line-item veto has increased their power over the Congress.
B) The United States became a simple free market economy.
C) The budget for government agencies has decreased leaving more responsibility to the president.
D) Modern presidents have to exercise powers as commander in chief, while earlier presidents did not.
E) The United States has increased prominence on the world stage.