Multi-choice problem: Continue writing the next sentence in this paragraph:

How to behave in a school science lab 
Know about all safety procedures. 
If an emergency does occur, it is important that you know the correct way to act. All safety and emergency procedures should be discussed at the beginning of the school year.

Available choices:
[i] If there is any question as to whether you are at risk, you can ask your school superior. Stay alert to potential dangers so you are prepared in case anything is fatal for your safety.;
[ii] In addition, relevant safety measures should be reviewed before each experiment. If you are unsure about a specific process, ask your teacher so that you will know exactly what to do.;
[iii] You should take a look at all the equipment and make sure everything is in good working order. Keep your classroom doors locked and other doors locked, both in and out, even during a scientific lab.;
[iv] If you are running, jumping, and doing dangerous experiments, make sure you know what to do. If there is a drop in the temperature, for example, evacuate your area.;
[ii]