The correct answer is: A. They did not give the central government enough power to act.
Here's why the other options are incorrect:
B. They did not give the states enough power to protect the people: While the Articles of Confederation did give states significant autonomy, this was precisely one of the factors contributing to the central government's weakness.
C. They gave the people the power to elect three branches of government: This statement is inaccurate. The Articles did not establish three branches of government at the federal level.
D. They allowed only the central government to collect taxes: The Articles actually prohibited the central government from directly levying taxes, further hindering its ability to function effectively.
The core weakness of the Articles of Confederation was the lack of power granted to the national government. It couldn't raise funds, regulate commerce, enforce laws, or maintain a standing army. This limited authority prevented the federal government from addressing critical issues and ultimately led to their revision under the Constitution, which established a stronger central government with clearly defined powers.