[单选题]
You are moving at 12u,in ;ckb7s 4rb: *npc0 km/h toward a stationary tra3j8:ypeoa 2m wz7nghw)7s+ajin. The train blows its 400-Hz whistlewzsh 3ew7 o2:aj pmag+ n)8jy7. Take the speed of sound to be 340 m/s. What frequency do you hear?
A. $444 \; Hz$
B. $439 \; Hz$
C. $364 \; Hz$
D. $361 \; Hz$
