Explanation:

Conventional sources of energy:
Conventional sources of energy are those that have been widely used for a long time and are the primary sources of energy for most human activities. These sources are primarily derived from fossil fuels, which include coal, oil, and natural gas. Other conventional sources of energy include hydro energy and biomass energy.

- Fossil fuel: Fossil fuels are the most widely used conventional sources of energy. They are formed from the remains of plants and animals that lived millions of years ago. Fossil fuels are burned to release energy in the form of heat or electricity.

- Biomass energy: Biomass energy is derived from organic matter, such as plants and agricultural waste. It can be used directly as a fuel or converted into other forms of energy, such as biogas or biofuels. Biomass energy is considered a conventional source because it has been used for centuries.

- Hydro energy: Hydro energy, also known as hydroelectric power, is generated by harnessing the power of flowing or falling water. It is a clean and renewable source of energy that has been used for many years. Hydroelectric power plants convert the energy of moving water into electricity.

Non-conventional source of energy:
- Solar energy: Solar energy is the energy derived from the sun. It is considered a non-conventional source because it does not rely on the burning of fossil fuels or the use of mechanical processes. Solar energy can be harnessed through the use of photovoltaic cells or solar thermal systems to generate electricity or heat.

Conclusion:
Based on the information provided, the correct answer is option 'B' - Solar energy. Solar energy is a non-conventional source of energy, as it does not rely on the burning of fossil fuels or mechanical processes. It is considered a renewable and sustainable source of energy that has gained significant attention in recent years due to its environmental benefits.