单选题 Smoking has been ______ in any public areas directly outside the building since the new regulations came into effect.

【正确答案】 B
【答案解析】句子应当是表示从过去的某个时间点开始到现在为止一直持续的某种状态，因此应填入现在完成时态的被动态。正确答案是(B)选项prohibited。