For a real gas, the chemical potential is given by

Answer: Option B

We know the property relation $$dG=VdP-sdT$$     for constant temperature $$dT=0$$
For an ideal gas
$$\begin{array}{rl}& dG=VdP\\ & dG=\frac{RT}{P}dP\\ & \Rightarrow dG=RTdlnP\end{array}$$
For a real gas also if we want to describe the relation in the same functional form we express it as $$dG=RTdlnf\Rightarrow d\mu =RTdlnf$$       where $$f=$$ fugacity, that means we buried the entire non ideality in this term fugacity. The term fugacity is also called as effective pressure.