Multi-choice problem: Continue writing the next sentence in this paragraph:

How to learn smoking tricks
Practice in a room with little air flow.
Windy days will make it impossible for even the best smoke tricksters to conjure up a trick. You want as little outside wind as possible, so stay away from fans, close the windows, and choose a still, quiet room.

Possible answers:
[A]. Use a tin or plastic ashtray to obscure the air flow from a pile of books. Keep magazines on the mantle or by your fireplace so they can catch the vapor when you tuck in your clothing.;
[B]. Blow up a fan to improve airflow by placing it near windows, and before proceeding, stand close to the window where you can hear the strongest air escaping. Try breathing in through your nose for three seconds, inhaling slowly through your mouth for three seconds before releasing.;
[C]. Make it an illusion that no smokers will smell or hear anything. There's nothing wrong with having no real smokers around, but if you can hide the smoke in a well-lit, empty room, your chances are your trick won't be noticed.;
[D]. Work on keeping the smoke in your mouth. The smoke will start to dissipate in your lungs, making it thinner and weaker.;
[D].