Answer:
Ah, I know I'm late to this but, the answer is 'A' XD
Step-by-step explanation:
My reason for thinking this is because the last three make no sense. If you were to use those, they'd be used incorrectly lol. For example: "Besides that, he teaches every lesson with a twist of creativity that delights his students." ...See? When using 'beside' that means you're switching to another topic. Again, sorry :')