For the reaction given below, 2.00 moles of A and 3.00 moles of B are placed in a 6.00-L container. At equilibrium, the concentration of A is 0.246 mol/L. What is the concentration of B at equilibrium? A) 0.246 mol/L B) 0.325 mol/L C) 0.500 mol/L D) 0.492 mol/L E) none of these