A – Wrong
Diamond does not have any intermolecular forces. It only has intramolecular forces which are strong covalent bonds between carbon atoms.
B – Wrong
In graphite, each carbon atom is only bonded to 3 other carbon atoms.
C – Wrong
Diamond is the hardest material on the planet whilst graphite is really soft.
D – Correct
All of these allotropes have only carbon atoms. They do not have any other elements. Therefore, they will react with O₂ to give the same products.
E – Wrong
Graphite can conduct electricity.