Sentence Correction

Hi Patrick,

I am really finding the GMATFix solution drills helpful. The questions are quite OG like and the video explanations helpful, with an added advantage that I can choose a question range for my question type.

The flash verbal lessons are good too and OG companion something which is a MUST practice, with its 30 seconds HACKS!

okay to getting back to the point,

Except for a gambling habit,_________.

A) Richard's flaws are virtually non-existent

B) there are no other flaws inherent to Richard

C) Richard has virtually no flaws.

I am not able to understand why A is the correct answer.
I am not able to digest that "Except for a gambling habit" is being compared to "Richard's flaws"

IMO C, somehow it sounds right and A seems a bit awkward.
could you please elaborate more on the answer.