The equation of state for a non-ideal gas is
\[
\frac{P v}{R T}=1+B P
\]
where $P$ is pressure, $v$ is specific volume, $R$ is the specific gas constant, $T$ is temperature, and $B$ is a temperature dependent parameter. For this gas, the partial derivative of enthalpy with respect to pressure at constant temperature is
- $B R T$
- $-R T^{2}\left(\frac{d B}{d T}\right)$
- $B R T-R T^{2}\left(\frac{d B}{d T}\right)$
- $0$
