Smog is a combination of

Options

A. fire and water
B. smoke and fog
C. water and smoke
D. air and water.

Explanation

**Step-by-Step Solution:**

1. **Understanding Smog**: Smog is a type of air pollution that is characterized by a mixture of smoke and fog. It is important to recognize the components that make up smog.

2. **Identifying Components**: Smog consists of various pollutants, including smoke particles, water vapor, and other gases such as oxides of nitrogen and sulfur.

3. **Analyzing the Options**:
- **Option A**: Fire and water - This does not accurately describe smog.
- **Option B**: Smoke and fog - This is a correct description of smog, as it is a combination of these two elements.
- **Option C**: Water and smoke - While these are components, it does not fully encompass the definition of smog.
- **Option D**: Air and water - This option does not specifically relate to smog.

4. **Conclusion**: Based on the analysis, the correct answer is **Option B: smoke and fog**.