Water pollution is

Options

A. presence of undesirable material in water
B. presence of sewage in water
C. presence of chemical fertilizer in water
D. All of the above

Explanation

**Step-by-Step Solution:**

1. **Understanding Water Pollution**:
- Water pollution refers to the contamination of water bodies (like rivers, lakes, oceans) due to harmful substances. This contamination can make the water unsafe for human consumption and can also disrupt the natural ecosystems that depend on that water.

2. **Identifying the Causes**:
- Common causes of water pollution include the discharge of sewage, industrial waste, agricultural runoff (like fertilizers and pesticides), and plastic waste. These substances introduce undesirable materials into the water.

3. **Effects of Water Pollution**:
- The presence of these harmful substances can lead to various health issues for humans and can also harm aquatic life. For example, pollutants can lead to the death of fish and other aquatic organisms, disrupt food chains, and degrade the quality of the water.

4. **Conclusion**:
- Based on the understanding of what water pollution is and its effects, we can conclude that the correct answer to the question regarding water pollution is the option that best describes it as the presence of undesirable materials in water that make it unsafe for human use and disrupts aquatic ecosystems.

5. **Selecting the Correct Option**:
- After analyzing the options provided, we find that Option D accurately reflects the definition and implications of water pollution.

**Final Answer**: Option D is the correct answer for the question regarding water pollution.

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