The equilibrium constant of a reaction:

Explanation:

The equilibrium constant is the ratio of the concentrations of the products to the reactants. 

The Equilibrium constant has no units  when the sum of the stoichiometric coefficients of reactants is equal to the sum of the stoichiometric coefficients of the products.

Hence, equilibrium constants of a reaction can be with or without units depending upon the stoichiometric coefficients of the species involved in a chemical equation.

Final Answer: Hence the correct answer is (B) can be with or without units depending upon the stoichiometric coefficients of the species involved in a chemical equation.