(A)VR1R2√R21+R22att=0andVR2att=∞(B)VR2att=0andV(R1+R2)R1R2att=∞(C)VR2att=0andVR1R2√R21+R22att=∞(D)V(R1+R2)R1R2att=0andVR2att=∞