A non-communicable disease is

Options

A. Measles
B. Rabies
C. Diphtheria
D. Diabetes

Explanation

### Step-by-Step Solution:

1. **Understanding Non-Communicable Diseases**:
- Non-communicable diseases (NCDs) are diseases that are not transmitted from one person to another. They do not have a specific infectious agent that can be passed through contact, air, or bodily fluids.

2. **Analyzing the Options**:
- **Measles**: This is a viral infection that spreads through respiratory droplets when an infected person coughs or sneezes. Therefore, it is a communicable disease.
- **Rabies**: This disease is caused by a virus that is transmitted through the saliva of infected animals, particularly through bites. Hence, it is also a communicable disease.
- **Diphtheria**: This is a bacterial infection that spreads through airborne droplets from an infected person. It is also classified as a communicable disease.
- **Diabetes**: This is a metabolic disorder that affects how the body processes blood sugar (glucose). It is not caused by an infectious agent and cannot be transmitted from one person to another. Thus, it is a non-communicable disease.

3. **Identifying the Non-Communicable Disease**:
- Among the options provided, only diabetes does not have a transmitting agent and is not communicable. Therefore, it is classified as a non-communicable disease.

4. **Conclusion**:
- The correct answer to the question "A non-communicable disease is" is **diabetes**.