using open flames to heat all materials keeping your cell phone on the laboratory countertop knowing where your instructor/laboratory leader is at all times removing your safety glasses when moving from station to station
I gave my students this multiple choice question: Which would be a safe practice to exercise during laboratory investigations?

Only one answer is correct among these 4 choices:
- using open flames to heat all materials
- keeping your cell phone on the laboratory countertop
- knowing where your instructor/laboratory leader is at all times
- removing your safety glasses when moving from station to station

Could you tell me which one is correct?

knowing where your instructor/laboratory leader is at all times