Mycorrhizae are found in:

Options

A. Oligotrophic soil
B. Eutrophic soil
C. Both of these
D. None of these

Explanation

**Step-by-Step Solution:**

1. **Understanding Mycorrhizae**: Mycorrhizae are a symbiotic association between fungi and the roots of higher plants. This means that both organisms benefit from each other. The fungus helps the plant absorb nutrients, while the plant provides food to the fungus through photosynthesis.

2. **Identifying Soil Types**:
- **Oligotrophic Soil**: This type of soil is characterized by a deficiency in one or more nutrients, making it less fertile.
- **Eutrophic Soil**: This soil is rich in nutrients and is typically more fertile.

3. **Analyzing the Options**:
- **Option A (Oligotrophic Soil)**: Since mycorrhizae help plants absorb nutrients, they are likely to be found in soils that lack nutrients, as they can assist in nutrient uptake.
- **Option B (Eutrophic Soil)**: While mycorrhizae can also be present in nutrient-rich soils, their primary role is to assist plants in nutrient-deficient environments.
- **Option C (Both of these)**: This option suggests that mycorrhizae are present in both types of soil.
- **Option D (None of these)**: This option suggests that mycorrhizae are not found in any of the mentioned soils.

4. **Conclusion**: Given that mycorrhizae are particularly beneficial in nutrient-deficient environments, they are primarily found in oligotrophic soil. Therefore, the correct answer is **Option A: Oligotrophic Soil**.

---