Which of the following Cannot be dated with radiocarbon C 14 dating?

For radiocarbon dating to be possible, the material must once have been part of a living organism. This means that things like stone, metal and pottery cannot usually be directly dated by this means unless there is some organic material embedded or left as a residue.

What material would be most suitable for carbon 14 dating?

Carbon-14 is a weakly radioactive isotope of Carbon; also known as radiocarbon, it is an isotopic chronometer. C-14 dating is only applicable to organic and some inorganic materials (not applicable to metals).