What legislative act established the United Kingdom of Great Britain and Ireland?

Okay, let's talk about the creation of the United Kingdom of Great Britain and Ireland. To understand this, we need to go back to the early 19th century. Before 1801, Great Britain (which was itself a union of England and Scotland created by the Act of Union 1707) and Ireland were separate entities, although Ireland was largely under British control. There was growing unrest in Ireland, culminating in the Irish Rebellion of 1798. British Prime Minister William Pitt the Younger believed that a political union would be the best way to secure both countries. So, after some political maneuvering and, frankly, bribery, the Act of Union was passed in 1800 and came into effect on January 1, 1801. This act dissolved the Irish Parliament and created the United Kingdom of Great Britain and Ireland, with a single parliament in Westminster. That's why the Act of Union is the correct answer; it's the specific piece of legislation that legally brought these nations together under one crown and one parliament. The other options are simply made-up names and don't reflect any actual historical events or legislative acts.