The correct answer is option 'B' which is 1776.

Explanation:
The United States of America was founded on July 4th, 1776, when the Continental Congress adopted the Declaration of Independence. This declaration announced that the thirteen American colonies, which were then at war with Great Britain, regarded themselves as thirteen newly independent sovereign states, and no longer a part of the British Empire. The signing of the Declaration of Independence marked the beginning of the American Revolution and the birth of the United States of America.

Some key points to note are:

- The Continental Congress was a meeting of delegates from the thirteen colonies that began in 1774 and continued until 1789.
- The American Revolution began in April 1775 with the Battles of Lexington and Concord, which were fought between American colonists and British soldiers.
- The Declaration of Independence was written by Thomas Jefferson, with input from other members of the Continental Congress. It declared that all men are created equal and have certain unalienable rights, including life, liberty, and the pursuit of happiness.
- After the Declaration of Independence was adopted, the Continental Congress became the Congress of the Confederation, which governed the United States until the Constitution was adopted in 1789.