Which of the Following Observations Does Not Relate Specifically to the Law

Which of the following observations does not relate specifically to the law of definite proportions?

A) Pure water is composed of the elements oxygen and hydrogen in a mass ratio of 8 to 1.
B) Any sample of a given compound always contains the same proportions by mass of the component elements.
C) The mass of the products of a chemical reaction is equal to the mass of the starting materials of the reaction.
D) When a metal reacts with oxygen, the oxygen content of the products is fixed at one or two values.
E) When water is broken down into its elements by electrolysis, elemental oxygen and hydrogen are formed in an 8 to 1 mass ratio.