Q. Assertion (A) Graphite conducts electricity.
Reason (R) Delocalisation of electrons occurs in graphite.

 266  143 The p-Block Elements Report Error

Solution:

In graphite, each carbon atom in hexagonal ring undergoes -hybridisation and makes three sigma bonds with three neighbouring carbon atoms. Fourth electron forms -bond. Due to delocalisation of this fourth electron, graphite conducts electricity.
Thus, both and are correct and is the correct explanation of .