A standing wave is formed between two loudspeakers that emit sound waves of frequency f 1.5 m. A student walking between the two loudspeakers finds that the distance between two consecutive sound maxima is 1.5 m. The speed of sound is 300 m s⁻¹. What is f?

A. 400 Hz
B. 200 Hz
C. 100 Hz
D. 50 Hz