Assertion (A) : The equilibrium constant is fixed and characteristic for any given chemical reaction at a specified temperature.
Reason (R) : The composition of the final equilibrium mixture at a particular temperature depends upon the starting amount of reactants.
A. Both A and R are true and R is the correct explanation of A.
B. Both A and R are true but R is not a correct explanation of A.
C. A is true but R is false
D. A is false but R is true.