Two loudspeakers are located 3.15 m apart on an outdoor stage. A listener is 16.3 m from one and 17.4 m from the other. During the sound chek, a signal generator drives the two speakers in phase with the same amplitude and frequency. The transmitted frequency is swept through the audible range (20 Hz - 20 kHz). The speed of sound in the air is 343 m/s. What are the three lowest frequencies that give minimum signal (destructive interference) at the listener's location? (a) Hz (lowest) (b) Hz (second lowest) (c) Hz (third lowest) What are the three lowest frequencies that give maximum signal (constructive interference) at the listener's location? (d) Hz (lowest) (e) Hz (second lowest) (f) Hz (third lowest)