The Term the "Critical Period," Coined by John Quincy Adams

The term the "Critical Period," coined by John Quincy Adams, refers to America under the Articles of Confederation. Why was the period from 1784-1787 so critical?

A) It was the time of the Revolutionary War in which Americans fought for their independence from Great Britain.
B) It was the years-long period the founding fathers took to write the Constitution, during which time America was lawless.
C) It was the time that American leaders developed major differences on politics, government, the economy, and foreign policy.
D) It was the worst period of George Washington's presidency, during which several small wars erupted.
E) It was a period during which the United States failed to take advantage of opportunities to expand and cede land in the West.