**Neither a teacher nor a native speaker.**
I agree with you although I'm 100% sure either...
A. Well, you don't affect the landlord's act (if he closes the bar or not) - and this makes me wonder if A. could be the right one.
C. makes no sense to me because he doesn't link two future moments, like:
"I'm sure the landlord will be closing this bar as soon as someone new wants to come in".
D. sounds very odd to me, and I doubt it's correct here.
- For Teachers