Ozone layer is being depleted. This is due to :

Options

A. `NO` emission from supersonic jets
B. chloroflurocarbon used as aerosols
C. both (A) and (B)
D. none of the above

Explanation

### Step-by-Step Solution:

1. **Understanding the Ozone Layer**: The ozone layer is a region of Earth's stratosphere that contains a high concentration of ozone (O3) and protects the planet from harmful ultraviolet (UV) radiation.

2. **Identifying Causes of Depletion**: The depletion of the ozone layer is primarily caused by certain pollutants, notably chlorofluorocarbons (CFCs) and nitrogen oxides (NOx).

3. **Role of Chlorofluorocarbons (CFCs)**: CFCs, which are used in aerosol sprays, refrigeration, and air conditioning, release chlorine atoms when they are broken down by UV light in the stratosphere. These chlorine atoms can react with ozone molecules, leading to the breakdown of ozone (O3) into oxygen (O2).

- **Chemical Reaction**:
- CFCs + UV light → Chlorine radicals
- Cl + O3 → ClO + O2

4. **Role of Nitrogen Oxides (NOx)**: Nitrogen oxides, particularly NO, are also released into the atmosphere from supersonic jets and other sources. These compounds can also contribute to ozone depletion by reacting with ozone.

- **Chemical Reaction**:
- NO + O3 → NO2 + O2

5. **Conclusion**: Both CFCs and NO emissions from supersonic jets contribute to the depletion of the ozone layer. Therefore, the correct answer to the question is that the ozone layer is being depleted due to both A (NO emissions from supersonic jets) and B (CFCs used as aerosols).

6. **Final Answer**: The correct option is "both A and B".