A real battery with electromotive force \(\mathcal{E}\) and internal resistance \(r\) has terminal voltage \(V_t\). The battery is connected to an external network where a fixed resistor of resistance \(R\) is in series with the positive terminal, followed by a junction that splits into two parallel branches: one branch containing a fixed shunt resistor of resistance \(R\) returning to the negative terminal, and the other branch containing a fixed resistor of resistance \(R\) in series with an adjustable load resistor \(R_L\) that also returns to the negative terminal. Which of the following expressions correctly gives the battery's terminal voltage \(V_t\) in the limit \(R_L \to 0\) and in the limit \(R_L \to \infty\)?