Which one of the following statements is NOT correct ?

Which one of the following statements is NOT correct ?

Buckminsterfullerene is an allotrope of carbon
Diamond is a good conductor of electricity
Graphite is a good conductor of electricity
In graphite, each carbon atom is linked to three other carbon atoms
This question was previously asked in
UPSC NDA-2 – 2020
The statement which is NOT correct is (B) Diamond is a good conductor of electricity. Diamond has a structure where each carbon atom is bonded to four other carbon atoms via strong covalent bonds. All valence electrons are tightly held in these bonds, meaning there are no free electrons to carry charge. Therefore, diamond is a poor conductor of electricity (a good electrical insulator).
Electrical conductivity in materials depends on the presence of free charge carriers, such as free electrons. The arrangement and bonding of atoms determine the availability of these carriers.
Statement (A) is correct: Buckminsterfullerene (C60) is a form of carbon, belonging to the fullerene family, which are allotropes of carbon. Statement (C) is correct: Graphite conducts electricity because each carbon atom is bonded to three others, leaving one delocalized electron per atom that can move throughout the layers. Statement (D) is correct: In graphite, carbon atoms are arranged in hexagonal layers where each carbon is covalently bonded to three other carbon atoms.