Answer
The function is homogeneous of degree 0
Work Step by Step
Given
\begin{aligned}
f(x, y)=2 \ln \frac{x}{y}
\end{aligned}
Since
\begin{aligned}
f(tx,t y)&=2 \ln \frac{tx}{ty}\\
&= 2 \ln \frac{x}{y}\\
&=f(x,y)
\end{aligned}
Then the function is homogeneous of degree 0
