A good vector in genetic engineering is :

Options

A. Agroba‹ teriiim tumefac'iens
B. Bacillus thuringiensis
C. Bacillus aInylolique[aciens
D. Salmonella typhimurium

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a good vector in genetic engineering from the given options: Agrobacterium tumefaciens, Bacillus thuringiensis, Bacillus Nilo lycoefficients, and Salmonella typhimurium.

2. **Identifying Types of Vectors**: In genetic engineering, vectors are vehicles used to transfer genetic material into a host organism. Common types of vectors include plasmids, viral vectors, cosmids, and artificial chromosomes.

3. **Evaluating the Options**:
- **Agrobacterium tumefaciens**: This bacterium is known for its ability to transfer DNA to plant cells, making it a widely used vector in plant genetic engineering.
- **Bacillus thuringiensis**: While it is a bacterium that produces insecticidal proteins, it is not primarily used as a vector in genetic engineering.
- **Bacillus Nilo lycoefficients**: This option is not widely recognized in the context of genetic engineering vectors.
- **Salmonella typhimurium**: This bacterium is primarily known for its role in pathogenicity and is not typically used as a vector.

4. **Conclusion**: Among the provided options, **Agrobacterium tumefaciens** is considered a good vector in genetic engineering due to its ability to effectively transfer genes into plant cells.

5. **Final Answer**: The good vector in genetic engineering is **Agrobacterium tumefaciens**.

---