В данном предложении правильный предлог для пропуска (4) — "of".
Таким образом, правильный вариант: "I’m a student 1) at the University of Glasgow in Scotland. Glasgow is 2) on the river Clyde. It’s an industrial city but it’s also famous 3) for its museums, the Glasgow School of Art and the Scottish opera. There are two popular football clubs 5) in Glasgow, Rangers and Celtic."
Ответ: of.
