What is the country residence of the Prime Minister?

The country residence of the Prime Minister is 10 Downing Street. This historic building has been the official residence of the Prime Minister of the United Kingdom since 1735 and serves as both a home and a place of work. It is centrally located in Westminster, London, and is known for its distinctive black door and significant role in UK government and politics.

The Prime Minister’s official engagements occur at this location, making it not just a private residence, but also a venue for meetings, press conferences, and other governmental functions. It's an important symbol of the office of the Prime Minister, representing the continuity of leadership and government within the UK.

Other locations mentioned, such as Buckingham Palace, are significant in their own right as the official residence of the monarch, but they do not serve as the Prime Minister's residence. Number 11 Downing Street is used as the Chancellor of the Exchequer's residence and office. Whitehall is a street in Westminster that houses several government offices and is known for its political significance, but it is not the residence of the Prime Minister. Therefore, 10 Downing Street is the correct and most relevant answer concerning the Prime Minister's country residence.