When the sediment turns into a rock, the decay becomes gas and petroleum after a million years.
This is evident because when sediments turn into rock, there will still be some remnants of plants and other organisms underneath in a seafloor area.
These organisms will then be subjected to extreme heat and temperature, thereby turning them into fossil fuels.
These fossil fuels are what are explored and turn into natural gas and crude oil/petroleum.
The process of transforming the sediments into fossil fuels usually takes million years.
Hence, in this case, it is concluded that the correct answer is option A. "Million years."
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