Hello, could you tell me with of the highlighted options are grammatically correct? Can I use both of them even if the text communicates a general observation? Thank you!

Secondly, a great teacher should be considerate. A/the goodeducator understands their pupils better than most people. A/The teacher understands whothey are, where they come from. A/Theteacher should know their abilities and limitations. A/The teacher should know their students and know how to help them inschool matters but also in social ones.