A 3-bus network is shown. Consider generators as ideal voltage sources. If rows 1, 2 and 3 of the Y_bus matrix correspond to bus 1, 2 and 3 respectively, then Y_bus of the network is

Options :

1. $\left[\begin{array}{ccc}-4j& j& j\\ j& -4j& j\\ j& j& -4j\end{array}\right]$

2. $\left[\begin{array}{ccc}-4j& 2j& 2j\\ 2j& -4j& 2j\\ 2j& 2j& -4j\end{array}\right]$

3. $\left[\begin{array}{ccc}-\frac{3}{4}j& \frac{1}{4}j& \frac{1}{4}j\\ \frac{1}{4}j& -\frac{3}{4}j& \frac{1}{4}j\\ \frac{1}{4}j& \frac{1}{4}j& -\frac{3}{4}j\end{array}\right]$

4. $\left[\begin{array}{ccc}-\frac{1}{2}j& \frac{1}{4}j& \frac{1}{4}j\\ \frac{1}{4}j& -\frac{1}{2}j& \frac{1}{4}j\\ \frac{1}{4}j& \frac{1}{4}j& -\frac{1}{2}j\end{array}\right]$