a field trip to a museum of geology a field investigation of rock layers in a hillside a laboratory demonstration on the hardness of minerals a laboratory investigation of the identification of fossils
I gave my students this multiple choice question: A hard hat would be used to protect a student during which type of investigation?

Only one answer is correct among these 4 choices:
- a field trip to a museum of geology
- a field investigation of rock layers in a hillside
- a laboratory demonstration on the hardness of minerals
- a laboratory investigation of the identification of fossils

Could you tell me which one is correct?

a field investigation of rock layers in a hillside