Answer:
Step-by-step explanation:
A: is fine. The speaker is pleased that his students succeeded. Nothing the matter with that.
B. Recollect is correctly used. She takes delight in embarrassing the you person.
C. Stupor is correctly used as well. It means falling into a state of near unconsciousness. So the person speaking is very tired.
D. is the answer. I don't have any idea what lagging means here. You want a word like complaining.