Which one is installed in the Elizabeth Tower in London?

Correct answer: Big Ben. Big Ben, the Great Bell, hangs inside the Elizabeth Tower (formerly the Clock Tower) at the Palace of Westminster.

• Water Westminster house: “Water Westminster house” is not a real structure.
• Eiffel Clock: The Eiffel Tower is in Paris and has no such clock.
• None of these: “None of these” is incorrect because Big Ben is correct.