Q7. Prof. Lee is driving along a highway at 25 m/s when he hears the siren of an emergency vehicle traveling in the opposite direction on the other side of the highway. When the vehicle is approaching him, he hears the frequency of the siren as 2300 Hz, but when it is past him the frequency becomes 1600 Hz. What is the speed of the vehicle? The speed of sound in air is 343 miss. (6 points) A) 37 m/s B) 32 m/s C) 30 m/s D) 41 m/s E) 50 m/s