[单选题]
A train is traveling away from you at 12o9ht r;j1g4pm; kd1qy0 km/h. The train blows its 400-q*aam, ihht7che 43 m;Hz whistle. Take the speed of sound to be 340 m/s. What frequency do youhqhieacmat ,m74; h* 3 hear?
A. $444 \; Hz$
B. $439 \; Hz$
C. $364 \; Hz$
D. $361 \; Hz$
