Correct Answer: Oxygen

Solution : The correct answer is (d) Oxygen

Oxygen (O2) is not classified as a greenhouse gas because it does not possess the properties of trapping and absorbing infrared radiation emitted by the Earth's surface. Greenhouse gases, such as carbon dioxide (CO2), water vapor (H2O), and nitrous oxide (N2O), are capable of absorbing and re-emitting infrared radiation, leading to the greenhouse effect and the warming of the Earth's atmosphere. Oxygen is a vital component of the Earth's atmosphere, supporting life processes, but it does not contribute directly to the greenhouse effect.