Q 79 的正确句子为 Denfense attorneys have occasionally argued that their clients' misconduct stemmed from reaction to sth ingested, but if criminal or delinquent behaviour is attributed to an allergy to some food, the perpetrators are in effect told thar they are not responsible for their actions. 我不大懂为什么这里要but转折呢?请大牛帮我翻译一下整句话的意思吧!谢谢