JEE Advanced 2013 Physics question

Two vehicles, each moving with speed u on the same horizontal straight road, are approaching each other. Wind blows along the road with velocity w. One of these vehicles blows a whistle of frequency . An observer in the other vehicle hears the frequency of the whistle to be . The speed of sound in still air is V. The correct statement(s) is (are)

• (A)If the wind blows from the observer to the source, .Correct
• (B)If the wind blows from the source to the observer, .Correct
• (C)If the wind blows from observer to the source, .
• (D)If the wind blows from the source to the observer, .