The answer for this question would be all of the above
1.5 it’s ethical In my opinion
If you eat less when you are in weight training, you will loose weight because you burn more calories in training then not. If you're calorie intake remains the same, you will burn more and lose more body fat.
I suggest, if this is a laptop given to you for school purposes, that you search through all the things downloaded on the laptop. You may find a screen sharing device or an application on the computer that allows the school to monitor your screen or what you've accessed. If you don't find anything of the sort downloaded on the computer you may be fine, although i would suggest doing small things at first, like scrolling through images or having multiple tabs open, so if it turns out they can see your screen you wont get in too much trouble. If nothing happens you may be fine. I do online school on my own laptop and no ones stopped me from tabbing around during lessons, but who knows. Good luck, fam.