When the rms voltages VL , VC and VR are measured respectively across the inductor L, the capacitor C and the resistor R in a series LCR circuit connected to an AC source, it is found that the ratio VL:VC:VR=1:2:3 . If the rms voltage of the AC source is 100 V, the VR is close to:
a. 50 V
b. 70 V
c. 90 V
d. 100 V