Critical Reasoning (CR) | Re: Editorial: The roof of Northtown Council’s equipment-storage

This is a causal argument. The author is assuming that because the building was otherwise built to code, the one departure must be responsible for the problem. Maybe there was some other cause of the collapse.

(B) provides this other cause. The snow was too much even for a built-to-code structure to withstand.

(A) actually strengthens the argument by suggesting that no building that conformed to code collapsed.
(C) hints that perhaps the building wasn't up to the best standard, but this is irrelevant.