The correct answer is option 3, constitutional monarchy. A constitutional monarchy is a form of government where a king or queen serves as the ceremonial head of state, while the actual governing power is exercised by an elected parliament or legislature. In the case of the United Kingdom, the monarch, currently Queen Elizabeth II, has limited powers and acts as a figurehead, representing the nation and performing symbolic duties. The actual political decision-making process is carried out by the elected officials in the UK Parliament, which includes the House of Commons and the House of Lords. The UK is often cited as a classic example of a constitutional monarchy due to its long history of balancing monarchy with parliamentary democracy.