Which one of the following pairs of statements about diamond and graphite is correct?
- ADiamond and graphite are both pure carbon. They are both macromolecules.
- BDiamond and graphite can both be used as electrodes. Graphite is also used as a lubricant.
- CDiamond has covalent bonds. Graphite has ionic bonds.
- DDiamond is hard with a high melting point. Graphite is soft with a low melting point.