Please answer question 6question and explain the solution

6. A musician is tuning her guitar by playing two strings simultaneously and listening for beats. The first string vibrates at 544 Hz and the second vibrates at 550 Hz. How many beats per minute will she hear? A. There will be no beats because the waves have different wavelengths B. 547 beats per minute D. 6 beats per minute E. 360 beats per minute