For the network shown, the equivalent Thevenin voltage and Thevenin impedance as seen across terminals ‘$\text{ab}$’ is
- $\text{10 V}$ in series with $12\:\Omega$
- $\text{65 V}$ in series with $15\:\Omega$
- $\text{50 V}$ in series with $2\:\Omega$
- $\text{35 V}$ in series with $2\:\Omega$