Final answer:
The value of Kc, an equilibrium constant, depends on both the concentrations of products [P] and reactants [R]. Kc increases with an increase in [P] and decreases when [R] is reduced, but remains constant at equilibrium.
Step-by-step explanation:
The correct statement for the expression Kc = [P]/[R] is C) The value of Kc depends upon both [R] and [P]. The equilibrium constant Kc is determined by the ratio of the concentration of the products [P] to the concentration of the reactants [R]. An increase in [P] would increase the value of Kc, and conversely, a decrease in [R] would also increase Kc as it would make the denominator smaller. When equilibrium is achieved, the concentrations of reactants and products remain constant, as does the value of Kc.