A non-renewable source of energy is

1. A

   Solar energy

   Solar energy is a renewable flow from the Sun. It is not a stock that is exhausted by use in the geological sense, so it is not the non-renewable source asked here.

2. B

   Petroleum

   Petroleum is a fossil hydrocarbon formed over millions of years. Once extracted and burnt, that stock is not replaced on a human timescale. That is the textbook non-renewable source, and the official key.

3. C

   Wind energy

   Wind energy is kinetic energy of moving air driven by solar heating. It is classed as renewable, not as a finite mineral fuel.

4. D

   Biogas

   Biogas is produced from contemporary biomass (dung, waste) and is treated as a renewable, replenishable fuel, not a fossil stock.

Summary. Official key is (b) petroleum. Non-renewable energy here means fossil stocks—coal, oil, natural gas—that nature does not refill within a human lifetime. Solar, wind and biogas are the renewable distractors in the same list. Do not confuse ‘stored chemical energy’ with ‘non-renewable’: wood stores energy but is renewable if grown again. Honour the stored letter (b).