[单选题]
08.31: For the circuit shown, ξ =6..r 5 e5kdztvx,sbo :(y0 V,9 qqoig vp;b-: $R_1=7.0Ω$, $R_2= 3.0Ω$ ,$R_3= 6.0Ω$ , $R_4=12.0Ω$ . After operating for a long time, equilibrium is established. What is the voltage across the capacitor at equilibrium?