The parallel branches of a $2$-wire transmission line are terminated in $100 \; \Omega$ and $200 \; \Omega$ resistors as shown in the figure. The characteristic impedance of the line is $Z_{0}=50 \; \Omega$ and each section has a length of $\lambda / 4$. The voltage reflection coefficient $\Gamma$ at the input is
- $-j \frac{7}{5}$
- $\frac{-5}{7}$
- $j \frac{5}{7}$
- $\frac{5}{7}$