How did the U.S. Constitution solve a problem created by the Articles of Confederation?

A. The Constitution created a bicameral legislature, allowing each state two ways of passing laws.
B. The Constitution created a national military l, where defense would not depend on donations form the states.
C. The Constitution created a Congress m, where each state would have one elected official to represent it.
D. The Constitution created an executive branch, allowing each state to lobby the president for vetoes.