The figure shows the per-phase representation of a phase-shifting transformer connected between buses $1$ and $2$, where $\alpha$ is a complex number with non-zero real and imaginary parts.
For the given circuit, $Y_{bus}$ and $Z_{bus}$ are bus admittance matrix and bus impedance matrix, respectively, each of size $2 \times 2$. Which one of the following statements is true?
- Both $Y_{bus}$ and $Z_{bus}$ are symmetric.
- $Y_{bus}$ is symmetric and $Z_{bus}$ is unsymmetric.
- $Y_{bus}$ is unsymmetric and $Z_{bus}$ is symmetric.
- Both $Y_{bus}$ and $Z_{bus}$ are unsymmetric.