Who was the longest serving PM in the 20th century?

問題： Who was the longest serving PM in the 20th century?

選擇：John Major
Sir Alec Douglas-Home
Robert Walpole
Margaret Thatcher

正確答案：
4

解釋:

Margaret Thatcher was the first woman Prime Minister of the UK. She was the longest-serving Prime Minister of the 20th century, remaining in office from 1979 until 1990.