Sentence Correction

Defense attorneys have occasionally argued that their clients' misconduct stemmed from a reaction to something ingested, but in attributing criminal or delinquent behavior to some food allergy, the perpetrators are in effect told that they are not responsible for their actions.

(A) in attributing criminal or delinquent behavior to some food allergy
(B) if criminal or delinquent behavior is attributed to an allergy to some food
(C) in attributing behavior that is criminal or delinquent to an allergy to some food
(D) if some food allergy is attributed as the cause of criminal or delinquent behavior
(E) in attributing a food allergy as the cause of criminal or delinquent behavior

How can (B) be the answer?
In MGMAT SC it is written that "use only one connector at a time".
In (B) there are two connectors placed together: 'but' and 'if'.
Please explain.

Thanks

sentence demands 2 connectors: (A,but B) and here B is (if C,D) where A,B,C,D are sort of sentences that need connectors in b/w