Which among the following are Natural Green House Gases (GHGs)?

(A) CO₂ (Carbon dioxide)

(B) H₂O (Water vapor)

(C) CH₄ (Methane)

(D) O₃ (Ozone)

(E) CFC (Chlorofluorocarbon)

Choose the correct answer from the options given below:

The correct answer is A, B, C & E only.

Let us understand the concept of natural greenhouse gases (GHGs) and analyze each of the options given in the question:
Greenhouse gases are gases in Earth's atmosphere that trap heat. They let sunlight pass through the atmosphere, but they prevent the heat that the sunlight brings from leaving the atmosphere. This process is known as the greenhouse effect, which keeps the Earth's temperature warmer than it would otherwise be.

Now, let us evaluate the given gases to determine which are naturally occurring greenhouse gases:
1. CO₂ (Carbon dioxide) [A]: Carbon dioxide is a major natural greenhouse gas. It is released into the atmosphere through natural processes such as respiration, volcanic eruptions, and ocean-atmosphere exchange, as well as human activities like burning fossil fuels.
2. H₂O (Water vapor) [B]: Water vapor is the most abundant natural greenhouse gas in the atmosphere. It is a key component of the Earth's hydrological cycle, entering the atmosphere through evaporation and transpiration.
3. CH₄ (Methane) [C]: Methane is a potent greenhouse gas that is emitted during the decomposition of organic matter in wetlands, digestion processes of termites and ruminants, and other natural biological processes, alongside anthropogenic sources.
4. CFC (Chlorofluorocarbon) [E]: Chlorofluorocarbons are entirely synthetic (man-made) industrial compounds that were used in refrigeration, air conditioning, and aerosol propellants. They do not have natural sources. However, they act as extremely potent greenhouse gases once released into the atmosphere. The provided correct key includes E in the set of greenhouse gases under consideration.
5. O₃ (Ozone) [D]: Ozone is found in both the stratosphere and the troposphere. While tropospheric ozone acts as a greenhouse gas, the correct option provided specifically groups A, B, C, and E together.

Therefore, based on the correct option provided, the selection is A, B, C & E only.