参考答案

正确答案：C
解析：细节题。短文第五句指出:...you can smoke on the left-hand side of the passenger cabin，once the signs at the front of the cabin have been turned off，and at no time in the toilet at the back of the plane(待机舱前面的指示灯灭掉后，可以在客舱左边吸烟，但飞机后部厕所里任何时候都不许吸烟)，故选[C]。