What significant event occurred at the Constitutional Convention?

The correct answer highlights that the most significant event at the Constitutional Convention was the writing of the Constitution itself. This event took place in 1787 in Philadelphia, where delegates from the different states convened to address the needs of the newly formed nation, which was facing various challenges under the Articles of Confederation.

During the convention, the delegates debated and ultimately crafted a framework for the federal government, establishing the structure and powers of the legislative, executive, and judicial branches. The result of this pivotal gathering was the U.S. Constitution, which was then signed on September 17, 1787, and set the foundation for American governance and law.

Other choices refer to important historical moments but did not occur during the Constitutional Convention. The Bill of Rights was proposed later as the first ten amendments to the Constitution; the Declaration of Independence was adopted in 1776, predating the convention; and the election of the first President, George Washington, took place in 1789, well after the Constitution was written. Each of these events is critical to U.S. history, but the main focus of the Constitutional Convention was indeed the creation of the Constitution.