The correct option is C Law of octaves worked quite well for lighter elements but failed for heavier elements.
John Newlands arranged the then discovered elements on the in the order of their incresing atomic masses.
He noticed that every eighth element exhibits similar properties as compared to the first element. He called this observation as the ‘Law of Octaves’ better known as ‘Newlands' Law of Octaves’.
Law of octaves worked quite well for lighter elements but failed with heavier elements. This is one of the demerits of Newlands' law of octaves.