In the bridge circuit shown, an ideal battery of potential difference \(V_0\) is connected across junctions \(A\) and \(D\). The upper branch consists of two resistors, \(R_1 = R\) and \(R_2 = 3R\), connected at node \(B\). The lower branch consists of two resistors, \(R_3 = 2R\) and \(R_4 = 2R\), connected at node \(C\). A central resistor of resistance \(R_0 = R\) connects node \(B\) to node \(C\). What is the direction of the electric current through the central resistor \(R_0\), and what is the magnitude of this current?