A. relatively narrow range of temperatures in which oil can form: 90°C to 160°C.
Explanation:
The formation of oil begins in warm, shallow oceans that were present on the Earth millions of years ago. In these oceans, extremely small dead organic matter - classified as plankton falls to the floor of the ocean.
If temperatures of the kerogen are greater than 90°C but lower than 160°C, the kerogen is transformed into oil and natural gas. At temperatures higher than this, only natural gas (literally a gas that's a hydrocarbon) or graphite is formed. This temperature range is known as the "oil window".
