In hydroponics :

Options

A. Cost of infrastructure is low
B. Soil borne pathogens are absent
C. Problem of weeding is present
D. pH is maintained at 7-8.

Answer

**Step-by-Step Solution:**

1. **Understanding Hydroponics**: Hydroponics is a method of growing plants without soil, using a nutrient-rich water solution. This technique allows for better control over nutrient delivery and can lead to healthier plants.

2. **Analyzing the Options**:
- **Cost of Infrastructure is Low**: This statement is incorrect. Hydroponics typically requires a significant investment in infrastructure, including systems for nutrient delivery, lighting, and climate control.
- **Soil Borne Pathogens are Absent**: This statement is correct. Since hydroponics does not use soil, it eliminates the risk of soil-borne diseases and pathogens that can affect plant health.
- **Problem of Weeding is Present**: This statement is incorrect. In hydroponics, since there is no soil, there are no weeds, which means the problem of weeding is absent.
- **pH is Maintained at 7 to 8**: This statement is incorrect. The optimal pH range for hydroponics is typically between 5.5 and 6.5, which allows for better nutrient absorption by the plants.

3. **Conclusion**: Based on the analysis of the options, the correct answer is that "soil borne pathogens are absent" in hydroponics.

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