The correct answer is option 4, Saudi Arabia. Saudi Arabia is the only country in the given list that is still governed by a monarch. The country is ruled by the House of Saud, which is a royal family. The monarch, known as the King of Saudi Arabia, holds significant power and authority in the country, including the ability to make decisions and govern the nation. This monarchial system of government has been in place in Saudi Arabia for many years. It is important to note that the other three options in the list (Afghanistan, Iran, Iraq) do not have a monarch and have different forms of government, such as presidential and parliamentary systems.