The correct answer is The Articles of Confederation did not give the federal government enough power to be effective.
The Articles of Confederation was America's first constitution after breaking free from Great Britain. With this new constitution, the Americans wanted to make a weaker central (aka federal) government. This was due to America's bad experience with a strong central government ran by King George III during the middle of the 18th century.
This is why the federal government did not have the ability to collect taxes, enforce national laws, or even raise an army. This constitution proved highly ineffective, as the federal government had no real power of the states. This is why the Articles of Confederation would eventually be replaced by the US Constitution.