Xanthomonas citri is related to

Options

A. Disease in Xanthium
B. Xanthophyceae
C. A virus
D. Citrus canker.

Answer

### Step-by-Step Solution:

1. **Identify the Organism**: The question asks about Xanthomonas citri, which is a type of bacteria. It is important to recognize that it belongs to the kingdom Monera, which includes prokaryotic organisms.

2. **Understand the Characteristics**: Xanthomonas citri is described as a rod-shaped, gram-negative bacterium. This classification helps in understanding its biological characteristics and its behavior in relation to other organisms.

3. **Determine the Disease Caused**: Xanthomonas citri is known to cause a specific disease called "citrus canker." This disease affects various citrus plants, including lemons, oranges, and grapefruits.

4. **Impact on Plants**: The disease manifests as leaf spotting and can lead to severe conditions such as fruit drop if the environmental conditions are favorable for the bacteria's growth.

5. **Examine the Options**: The options provided in the question include:
- Xanthium
- Xanthophyceae
- A virus
- Citrus canker

6. **Eliminate Incorrect Options**:
- Xanthium is a plant but not directly related to Xanthomonas citri.
- Xanthophyceae refers to yellow-green algae, which are not related to this bacterium.
- A virus is not applicable since Xanthomonas citri is a bacterium, not a virus.

7. **Select the Correct Answer**: The only option that correctly relates to Xanthomonas citri is "citrus canker," as it is the disease caused by this bacterium.

### Final Answer:
Xanthomonas citri is related to **citrus canker**.

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