Tuberculosis is quite common among

Options

A. Undernourished people
B. People living in dingy urban localities
C. People living in isolated villages
D. Both A and B

Answer

**Step-by-Step Solution:**

1. **Understanding Tuberculosis (TB)**:
- Tuberculosis is an infectious disease primarily caused by the bacterium Mycobacterium tuberculosis. It mainly affects the lungs but can also impact other parts of the body.

2. **Identifying Risk Factors**:
- TB is more prevalent in certain populations due to various factors. The two significant groups mentioned in the question are:
- Undernourished people
- People living in dingy urban localities

3. **Analyzing Undernourished People**:
- Undernourished individuals have weakened immune systems, making them more susceptible to infections, including tuberculosis. This leads to an increased severity and frequency of diseases.

4. **Analyzing People Living in Dingy Urban Localities**:
- Overcrowded and poorly maintained urban areas often have higher rates of TB transmission due to close contact among individuals, poor ventilation, and inadequate healthcare facilities.

5. **Considering Isolated Villages**:
- While TB can occur in isolated villages, the conditions in undernourished populations and overcrowded urban settings are more conducive to the spread of the disease.

6. **Conclusion**:
- Based on the analysis, TB is quite common among both undernourished people and those living in dingy urban localities. Therefore, the correct answer is option D: both A and B.