Match List I and List II 

1-B; 2-A; 3-C; 4-D

The correct answer is option 1. 1-B; 2-A; 3-C; 4-D.

1. Diamond - B. Hardest natural material: Diamond is known for its exceptional hardness, making it the hardest natural material on Earth. This property is due to its unique crystal structure and strong covalent bonds between carbon atoms.

2. Graphite - A. Good conductor of electricity: Graphite is a form of carbon with a layered structure. Although it's a non-metal, it has delocalized electrons that can move freely between layers, making it an excellent conductor of electricity.

3. Sodium - C. Soft metal:  Sodium is a highly reactive alkali metal that is soft and can be easily cut with a knife. It has a low melting point and is malleable, characteristics commonly associated with soft metals.

4. Silver - D. Good conductor of heat:  Silver is well-known for its high thermal conductivity, which means it can efficiently transfer heat. This property makes silver widely used in applications where heat conduction is important, such as in electrical contacts and thermal conductors.