Mycorrhiza is found in

Options

A. oligotrophic soil
B. eutrophic soil
C. Saline soils
D. none of these

Explanation

### Step-by-Step Solution:

1. **Definition of Mycorrhiza**:
- Mycorrhiza refers to a symbiotic association between fungi and plant roots. The term "myco" means fungi, and "rhiza" means roots.

2. **Function of Mycorrhiza**:
- The primary role of mycorrhiza is to enhance the absorption of water and essential minerals from the soil for the plant. In return, the plant supplies carbohydrates (food) to the fungi.

3. **Nature of the Relationship**:
- This relationship is mutualistic, meaning both the fungi and the plants benefit from each other. The fungi help the plants to absorb nutrients more efficiently, while the plants provide food to the fungi.

4. **Presence in Soil Types**:
- Mycorrhiza is typically found in oligotrophic soils. Oligotrophic soils are characterized by low nutrient availability. The fungi assist plants in these nutrient-poor conditions to improve their nutrient uptake.

5. **Comparison with Eutrophic Soil**:
- In contrast, eutrophic soils have a normal or high level of nutrients. Mycorrhiza is not typically found in these soils because the nutrient availability is sufficient for plant growth without the need for fungal assistance.

### Final Answer:
Mycorrhiza is found in oligotrophic soils, where nutrient availability is low, and plants require the assistance of fungi for better absorption of water and minerals.

---