For the circuit, generate circuit diagrams that include only those elements that have current flowing through them and find the current flowing through R4 (direction from top to bottom) for times- (a) t < 0, IR4 = [ Select ] A (b) 0 < t < 2 s, IR4 = [ Select ] A (c) t > 2 s, IR4 = [ Select ] A Assume, V1 = 12V, V2 = 8V and all resistors are 2 ohms each