The Equilibrium Constant for the Reaction That Breaks Down Each

Multiple Choice

The equilibrium constant for the reaction that breaks down each molecule of substrate A to one molecule of B and one molecule of C is equal to 0.5. Starting with a mixture containing only molecules A at 1 M concentration, what will be the concentration of molecule A after reaching equilibrium under these conditions?

A) 0.5 M
B) 0.25 M
C) 0.125 M
D) 0.333 M
E) 0.667 M