Joke Collection Website - Bulletin headlines - The main reasons why fireworks must be prohibited in flour mills are (a) to prevent fires, (b) to prevent flour pollution, and (c) smoking is harmful to health.

The main reasons why fireworks must be prohibited in flour mills are (a) to prevent fires, (b) to prevent flour pollution, and (c) smoking is harmful to health.

There is a lot of flour dust around the flour processing plant. When it diffuses in the air and comes into full contact with the air, it is easy to explode, so the slogan "No Fireworks" should be posted.

So choose D.