Smoking, which may be a pleasure for some people, is a serious source of discomfort for their fellows. Medical authorities express their【31】about the effect of smoking on the health not only【32】those who smoke but also of those who do not. In fact, nonsmokers who must involuntarily inhale the air polluted by the tobacco smoke may【33】more than the smokers themselves.
As you are doubtless aware, a considerable number of our students have【34】an effort to【35】the university to ban smoking in the classrooms. I believe they are entirely right in their aim.【36】, I would hope that it is possible to achieve this by【37】on the smokers to use good judgment and show concern for others rather than【38】regulation.
Smoking is prohibited by city laws in theaters and in halls used for showing films as well as in laboratories【39】there may be a fire hazard. Elsewhere, it is up to your good sense.
I am therefore asking you to maintain "No Smoking" in the auditoriums and classrooms. This will prove that you have to keep nonsmokers' health and well-being【40】, which is very important to a large number of our students.
(31)

A. concern
B. trouble
C. interest
D. displeasure