After the Constitutional Convention in 1787, the Purpose Behind Disallowing

After the Constitutional Convention in 1787, the purpose behind disallowing states from making their own money was to:

A) retain the supremacy of the Constitution over state laws.
B) make Congress the most powerful branch of government.
C) ensure the necessary balance between the state and federal powers.
D) resolve the conflict between the southern states and the northern states.
E) promote economic and social stability in the states.