I would say try to learn it every time also always test yourself, for a student and a adult teaching try to get the student happy because it the student is upset they won't get anywere. Hopefully that helps you ❤
I know the answer isn't C or D. A or B both seem likely until you see that B involves a 'comma without a conjunction,' either way you should never put a comma before 'and'; I am not sure why but I am pretty sure this only applies in a formal document. So your answer is A.