Which of the following is NOT a fossil fuel?

Biomass

The correct answer is option 2. Biomass.

Biomass is NOT a fossil fuel.

1. Asphalt:  Asphalt is a derivative of petroleum and is considered a fossil fuel product.

2. Biomass:  Biomass includes organic materials from plants and animals. It is not a fossil fuel because it is derived from recently living organisms. Examples of biomass include wood, agricultural crops, and organic waste.

3. Bitumen: Bitumen is a thick, sticky form of petroleum. It is a fossil fuel and is often found in natural deposits or can be obtained from the upgrading of heavy crude oil.

4. Petroleum:  Petroleum, commonly known as crude oil, is a fossil fuel. It is formed from the remains of ancient marine organisms.

Therefore, the correct answer is 2. Biomass.