I think the answer is A. You become a legal adult at the age of 18 .
Answer: D) a mental set
Explanation:
His mental set is giving him a procedure of wrong ways into the solving-problems. He is having mental set where he is convinced that the children will listen to him and that they will do their homework only if he is giving them threats which means that he is trying to control them with anger and fear.
Since his mental set is in a wrong way, he does not believe that kindness will bring him more productivity in class.
Because those broken equipment and glassware might eventually hurt other people around it.
You should tell your teacher (because your teacher is responsible for the well being of all the students in the class) and so he/she could bring up that problem to the school management and replace that equipment/ glassware for the new one.
