Biofertilisers include

Options

A. Blue-gree algae, rhizobia, other nitrogen-fixing bacteria and mycorrhizal fungi
B. Blue-green, algae, rhizobia and other nitrogen-fixing bacteria
C. Rhizobia, other nitrogen-fixing bacteria and mycorrhizal fungi
D. Blue-green algae, rhizobia and mycorrhizal fungi

Answer

**Step-by-Step Solution:**

1. **Understanding Biofertilizers**: Biofertilizers are substances that contain living microorganisms which promote plant growth by increasing the availability of nutrients to the plants. They are used to enhance soil fertility and crop productivity.

2. **Components of Biofertilizers**: The main components typically included in biofertilizers are:
- **Nitrogen-fixing bacteria**: These bacteria convert atmospheric nitrogen into a form that plants can use. Examples include *Rhizobia* and other nitrogen-fixing bacteria.
- **Cyanobacteria (Blue-green algae)**: These organisms also fix nitrogen and contribute to soil fertility.
- **Mycorrhizal fungi**: These fungi form symbiotic relationships with plant roots, enhancing nutrient uptake, particularly phosphorus.

3. **Analyzing the Options**:
- **Option 1**: Blue-green algae, rhizobia, other nitrogen-fixing bacteria, and mycorrhizal fungi.
- **Option 2**: Blue-green algae, rhizobia, and other nitrogen-fixing bacteria.
- **Option 3**: Rhizobia, other nitrogen-fixing bacteria, and mycorrhizal fungi.
- **Option 4**: Blue-green algae, rhizobia, and mycorrhizal fungi.

4. **Identifying the Correct Answer**:
- The first option includes all the key components of biofertilizers: blue-green algae, rhizobia, other nitrogen-fixing bacteria, and mycorrhizal fungi.
- The other options are missing at least one of these essential components.

5. **Conclusion**: Therefore, the correct answer is **Option 1**: Blue-green algae, rhizobia, other nitrogen-fixing bacteria, and mycorrhizal fungi.

---