The light from the cities makes it hard to see stars. The noise from the cities vibrates the telescopes. The power lines from the cities produce interference waves. The pollution from the cities reflects starlight.
I gave my students this multiple choice question: Why are many telescopes used far from cities?

Only one answer is correct among these 4 choices:
- The light from the cities makes it hard to see stars.
- The noise from the cities vibrates the telescopes.
- The power lines from the cities produce interference waves.
- The pollution from the cities reflects starlight.

Could you tell me which one is correct?

The light from the cities makes it hard to see stars.