An organism used as biofertilizer for raising soyabean crop is
Or
Most famous nitrogen fixing bacterium/biofertilizer is

Options

A. Nitrobacter
B. Nitrosomonas
C. Nitrococcus
D. Rhizobium

Answer

**Step-by-Step Solution:**

1. **Understand the Question**: The question asks for an organism that acts as a biofertilizer for raising soybean crops or the most famous nitrogen-fixing bacterium.

2. **Identify the Options**: The options provided are:
- A) Nitrobacter
- B) Nitrosomonas
- C) Nitrococcus
- D) Rhizobium

3. **Recall the Role of Nitrogen-Fixing Bacteria**: Nitrogen-fixing bacteria are essential for converting atmospheric nitrogen into a form that plants can use. This is particularly important for leguminous plants.

4. **Focus on Leguminous Plants**: Soybean is a leguminous plant, which means it has a symbiotic relationship with nitrogen-fixing bacteria.

5. **Identify the Correct Bacterium**: Among the options, Rhizobium is well-known for its association with leguminous plants, forming root nodules where nitrogen fixation occurs.

6. **Conclusion**: Therefore, the organism used as a biofertilizer for raising soybean crops is **Rhizobium**.

**Final Answer**: D) Rhizobium

---