The gas which occurs above the petroleum oil trapped under the rocks is called :

Options

A. biogas
B. petroleum gas
C. natural gas
D. coal gas

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the name of the gas that is found above petroleum oil, which is trapped under rocks.

2. **Identifying the Layers**: In geological formations, there are typically three layers: water at the bottom, petroleum oil above the water, and gas above the oil. This is due to the differences in density among these substances.

3. **Recognizing the Gas**: The gas that is commonly found above petroleum oil in these geological formations is known as natural gas.

4. **Distinguishing from Other Gases**: It's important to differentiate natural gas from other types of gases such as biogas, which is produced from the decomposition of organic matter, and petroleum gas, which is obtained from refining petroleum oil.

5. **Conclusion**: Therefore, the gas that occurs above the petroleum oil trapped under the rocks is called **natural gas**.

**Final Answer**: Natural gas

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