For an adiabatic expansion of an ideal gas, the fractional change in its pressure is equal to (where $$\gamma$$ is the ratio of specific heats):

A

$$-\gamma \frac{dV}{V}$$

B

$$-\gamma \frac{V}{dV}$$

C

$$-\frac{1}{\gamma} \frac{dV}{V}$$

D

$$\frac{dV}{V}$$