The strain of this fungi are used for the production of citric acid .

Options

A. Aspergillus fumigatus
B. A. flavus
C. A. niger
D. Rhizopus

Answer

To solve the question regarding which strain of fungi is used for the production of citric acid, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Question**: The question asks for the specific strain of fungi that is used in the production of citric acid.

2. **Review the Options**: The options provided are:
- A) Aspergillus fumigatus
- B) Aspergillus flavus
- C) Aspergillus niger
- D) Rhizopus

3. **Recall Knowledge of Fungi**: From previous knowledge or studies, we know that certain fungi are utilized in industrial processes, including the production of organic acids.

4. **Focus on Citric Acid Production**: Citric acid is a common organic acid used in food and beverage industries, and it is known to be produced by specific strains of fungi.

5. **Identify the Correct Fungus**: Among the options, Aspergillus niger is widely recognized for its role in the production of citric acid. It is the most common fungus used for this purpose.

6. **Confirm the Answer**: Based on the information gathered, the correct answer is C) Aspergillus niger.

### Final Answer:
The strain of fungi used for the production of citric acid is **C) Aspergillus niger**.

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