The weather symbol "s" means () A. Dust B. Floating dust C. Dust D. Frost.

On the weather forecast chart, we can see some symbols, which are used to represent the weather conditions, and they all have specific meanings. Only by knowing all kinds of weather symbols can we understand the weather forecast and serve our life and production. The symbol "S" in the stem represents floating dust, the upward arrow in the middle of "S" represents floating dust, the single arrow to the right of "S" represents sandstorm, and the double arrow to the right of "S" represents sandstorm.

Therefore, choose: B.