One mole of H₂O and one mole of CO are taken in a 10 L vessel and heated to 725 K. At equilibrium, 40% of water (by mass) reacts with CO according to the equation H₂​O(g)+CO(g)→H2​(g)+CO₂​(g). What is the equilibrium constant (Kc) for the reaction?

A. 2.5×10⁻²
B. 1.5×10⁻²
C. 2.0×10⁻²