Choose the odd-one out.

Explanation:Conventional energy sourceConventional energy sources are the natural energy resources which are present in a limited quantity and are being used for a long time.If once they are depleted, called non-renewable sources, being used up more quickly than it can replace itself.They are formed from decaying matter over hundreds of millions of years.These resources have been depleted to a great extent due to their continuous exploitation.Examples of conventional sources of energy include COAL, PETROLEUM, biomass, natural GAS and electricity.Non-Conventional energy sourceNon-conventional sources of energy are the energy sources which are renewable by natural processes.These cannot be EXHAUSTED easily, can be generated constantly so can be used again and again.These sources do not pollute the environment and do not require heavy expenditure. They are called renewable resources as they can be replaced through natural processes at a rate equal to or greater than the rate at which they are consumed.The various non-conventional energy sources in which technological developments are under process to harness energy for power generation.Solar energyWind energyEnergy from biomass and biogasTidal energyHydrogen energyOcean thermal energyGeothermal energyFuell cellsHence, Coal will be the odd-one out since REST all are non-conventional energy sources.