Select the correct option based on statements below:

Assertion (A): Graphite is a good conductor of electricity. However, diamond belongs to the category of insulators.
Reason (R): Graphite is soft in nature whereas diamond is very hard and brittle.
 
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true but (R) is not the correct explanation of (A).
3. (A) is true but (R) is false.
4. (A) is false but (R) is true.

Hint: Graphite has delocalised electrons,
Graphite has delocalised electrons, just like metals. These electrons are free to move between the layers in graphite, so graphite can conduct electricity.
On the other hand, diamonds have a tetrahedral arrangements with no unpaired electrons. Therefore, diamond is hard and brittle but insulator.