Why was the articles of confederation discarded?

The Articles of Confederation were discarded because the Federalists or those who sought to create a stronger national government in the writing of the Constitution won the debate. Their work helped to lay the groundwork for a federal system of states with a strong central government with specific powers assigned to it that were previously state powers in the Article's of Confederation. The Article's of Confederation were a step in this process, but were ultimately discarded for the creation of a stronger centralized government rather than a loose union of states like was created by the Article's of Confederation. 

Ithink it would be choices a and b. hope this !