@Matt and All,
I think, the key differentiator here is the difference in usage of Aggravating vs Aggravate. (idiomatic)
Aggravating means: Annoying or irritating.
Aggravate means: To worsen something.
I think with this we should be able to zero down to choice E. Usage of Aggravating in the sentence's context, as in choice A, is nonsensical.
Thanks,
Vaibhav.