Select the mismatched pair.

Options

A. Symbiotic bacteria-Rhizobium, Frankia
B. Symbiotic cyanobacteria-Frankia, Aulosira
C. Free-living bacteria-Beijerinckia, Azotobacter
D. none of these

Explanation

To solve the question of selecting the mismatched pair from the given options, let's analyze each option step by step:

### Step 1: Understand the Terms
- **Symbiotic Bacteria**: These are bacteria that form a mutualistic relationship with a host (plant, animal, or fungus), where both parties benefit.
- **Cyanobacteria**: These are photosynthetic bacteria that can fix nitrogen and can also form symbiotic relationships with various eukaryotes.

### Step 2: Analyze Each Option
1. **Symbiotic Bacteria Rhizobium, Francia**
- **Rhizobium**: This bacterium forms a symbiotic relationship with leguminous plants, aiding in nitrogen fixation.
- **Francia**: This is another genus of bacteria that forms symbiotic relationships, particularly with actinorhizal plants.
- **Conclusion**: This pair is matched correctly.

2. **Symbiotic Cyanobacteria, Francia, Allocera**
- **Francia**: As mentioned, it is a symbiotic bacterium.
- **Allocera**: This is not a recognized symbiotic cyanobacterium. This seems to be the mismatched part.
- **Conclusion**: This pair is mismatched.

3. **Free-living Bacteria, Bacterinica, and Azotobacter**
- **Bacterinica**: This term is not commonly recognized in the context of free-living bacteria.
- **Azotobacter**: This is a well-known free-living nitrogen-fixing bacterium.
- **Conclusion**: This pair is potentially mismatched due to "Bacterinica."

4. **None of these**
- This option suggests that all previous pairs are correctly matched, which is not the case.

### Step 3: Identify the Mismatched Pair
Based on the analysis, the mismatched pair is:
- **Symbiotic Cyanobacteria, Francia, Allocera** (because Allocera does not fit as a recognized symbiotic cyanobacterium).

### Final Answer
The mismatched pair is **Symbiotic Cyanobacteria, Francia, Allocera**.

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