Question

The solid(s) which cannot conduct electricity is/are:

• A. Caesium
• B. Graphite
• C. Diamond
• D. All of the above.

Answer 1

The correct option is C Diamond

$Cs$ is a metal. So it is a good conductor of electricity.
Covalent solids can't conduct electricity.
Diamond is insulator and is a covalent solid.
Even though graphite is a covalent solid, it can conduct electricity due to the presence of delocalised electrons in it.