`T_i` plasmids used in genetic engineering is obtained from

Options

A. Bacillus thuringiensis
B. Agrobacterium rhizogenes
C. Agrobacterium tumefaciens
D. Pseudomonas syringae

Answer

To answer the question about the source of Ti plasmids used in genetic engineering, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Term "Ti Plasmid":**
- Ti stands for "tumor inducing." These plasmids are known for their ability to induce tumors in plants.

2. **Identify the Source of Ti Plasmids:**
- Ti plasmids are specifically associated with a certain type of bacterium that is known to cause tumors in plants.

3. **Know the Bacteria Involved:**
- The bacterium that contains Ti plasmids is **Agrobacterium tumefaciens**. This bacterium is responsible for causing crown gall disease in plants.

4. **Review the Options Given:**
- A) Bacillus thuringiensis
- B) Agrobacterium rhizogenes
- C) Agrobacterium tumefaciens
- D) Pseudomonas syringae

5. **Select the Correct Answer:**
- Among the options, **Agrobacterium tumefaciens** is the correct answer, as it is the source of Ti plasmids used in genetic engineering.

### Final Answer:
The Ti plasmids used in genetic engineering are obtained from **Agrobacterium tumefaciens** (Option C).

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