The value of this parameter in a plasma is proportional to the square root of the adiabatic index. The SOFAR channel has a minimum value of this property and is located 1000 meters below the ocean. Taking the square root of the bulk modulus over density yields this quantity in liquids. The Prandtl-Glauert singularity was predicted to occur after exceeding this property. In dry air, this quantity equals about 343 meters per second. Dividing an object's velocity by this quantity gives its Mach number. For 10 points, name this quantity, the rate that acoustic waves move in a medium.
a) Frequency
b) Speed of light
c) Speed of sound
d) Wavelength