Sewer smells coming from a floor drain in a washroom can be a problem if the floors of the washroom are not cleaned often. Which of the following courses of action is the simplest way to stop the smell from coming out of the drain?
a) Pour a pail of water in the drain.
b) Cover the drain opening.
c) Sanitize the washroom.
d) Flush the drain with caustic soda.
e) Improve the washroom's ventilation.
Answer: A