Выбрите правильную букву вместо "? ": the longest metro is in london. it is called "? " and is 4000 metres kilometers long. a) the traffic b) the tube c) the drive d) rail way ! это монитроринг за 1-4 класс!

The longest metro is in London. It is called "?" and is 4000 metres kilometers long.
A) the Traffic        B) the Tube       C) the Drive       D) Rail Way