making a model of outer space asking questions to other scientists collecting information about planets looking at the night sky with a telescope
I gave my students this multiple choice question: Which of these would best help a scientist discover a new planet?

Only one answer is correct among these 4 choices:
- making a model of outer space
- asking questions to other scientists
- collecting information about planets
- looking at the night sky with a telescope

Could you tell me which one is correct?

looking at the night sky with a telescope