Which of the following causes water pollution?

All of the above

The correct answer is option 4. All of the above.

All of the above causes water pollution. Each of the mentioned activities contributes to water pollution:

1. Disposal of untreated sewage into water bodies: Untreated sewage contains various contaminants, including pathogens, nutrients, and organic matter, which can pollute water bodies and pose risks to human health and ecosystems.

2. Excessive use of pesticides and fertilizers: Agricultural runoff containing excessive pesticides and fertilizers can enter water bodies, leading to water pollution. These chemicals can harm aquatic ecosystems, disrupt the balance of aquatic life, and negatively impact water quality.

3. Disposal of untreated industrial waste into water bodies: Industrial activities often generate pollutants that, if not properly treated, can be discharged into water bodies. Industrial effluents may contain harmful chemicals, heavy metals, and other pollutants, causing water pollution and ecological damage.

Therefore, the correct option is All of the above.