Identify the source of energy from the given features A and B: A. It is a…

Sources of energy are broadly grouped into conventional sources — long-established, chiefly non-renewable fossil fuels such as coal, petroleum and natural gas, formed over millions of years underground — and non-conventional sources — comparatively newer-harnessed, naturally replenished options such as biogas, solar, wind and geothermal energy (at the school level these two groupings are commonly treated as synonymous with non-renewable and renewable respectively, though the correspondence is a teaching convention rather than a strict logical identity). Natural gas is a fossil-fuel hydrocarbon that occurs in underground reservoirs, very often trapped directly above or dissolved within crude-oil deposits.

Feature A places the source among the conventional group, consistent with natural gas being a fossil fuel formed from ancient organic matter over geological time. Feature B describes a source released when crude oil is brought to the surface — natural gas commonly occurs as associated gas sitting above or dissolved in petroleum reservoirs, escaping toward the surface as the oil is drilled and extracted.

Cross-check against the other named sources:

• Biogas is produced by anaerobic (microbial) decomposition of organic waste such as cattle dung and plant matter — a non-conventional source generated from biological waste rather than from underground hydrocarbon reservoirs.

• Geo-thermal energy is heat stored deep within the Earth's crust and mantle, tapped through hot springs, geysers, or drilled wells — a non-conventional source rooted in the planet's internal heat, unconnected to petroleum deposits.

• Wax (paraffin wax) is a solid hydrocarbon obtained by refining petroleum after extraction — a downstream refinery product rather than a source present within the reservoir itself.

The feature set — a conventional, fossil-fuel source released alongside crude oil at the surface — identifies natural gas.