The velocities of sound in air and water are 336 m / s and 1470 m/s respectively. Two sources producing waves of wavelength 6 m and 7 m sounded togather will produce beats

• A. That can be heard in both the media
• B. That can be heard only in water and not in air
• C. That can be heard only in air and not in water
• D. That can not be heard in either media