Which of the following diseases is associated with smoking?

Options

A. Bronchitis
B. Emphysema
C. Lung cancer
D. All of these

Answer

To determine which diseases are associated with smoking, we can analyze the options provided.

### Step-by-Step Solution:

1. **Identify the diseases listed in the options**:
- Option a: Bronchitis
- Option b: Emphysema
- Option c: Lung cancer
- Option d: All of these

2. **Understand the effects of smoking**:
- Smoking is known to cause a variety of health issues, particularly affecting the respiratory system and leading to several diseases.

3. **Examine each option**:
- **Bronchitis**: This is an inflammation of the bronchial tubes, and smoking is a major cause of chronic bronchitis.
- **Emphysema**: This is a condition that involves damage to the air sacs in the lungs, and it is also a part of chronic obstructive pulmonary disease (COPD) caused by smoking.
- **Lung Cancer**: Smoking is the leading cause of lung cancer, significantly increasing the risk of developing this disease.

4. **Conclusion**:
- Since smoking is associated with bronchitis, emphysema, and lung cancer, we can conclude that all the diseases listed in the options are indeed associated with smoking.

5. **Final Answer**:
- Therefore, the correct answer is option d: all of these.