What is the formula for speed of sound in terms of pressure and density?

• A. a=\(\sqrt{\frac{\gamma P}{\rho}}\)
• B. a=\(\sqrt{\frac{\gamma\rho}{P}}\)
• C. a=\(\sqrt{\frac{\gamma RP}{\rho}}\)
• D. a=\(\sqrt{\frac{\gamma P}{\rho R}}\)