Companion cells are

Options

A. small, thin walled living, enucleated
B. living, narrow, elongated, thin walled, nucleated
C. small, thick walled, living, nucleated
D. large, thick walled nucleated

Answer

### Step-by-Step Solution:

1. **Definition of Companion Cells**: Companion cells are specialized cells found in the phloem tissue of flowering plants. They are closely associated with sieve elements (sieve tubes) and play a crucial role in the transport of nutrients.

2. **Characteristics of Companion Cells**:
- **Living Cells**: Companion cells are living cells, meaning they contain cytoplasm and are metabolically active.
- **Thin Cell Walls**: They have thin cell walls which facilitate the movement of substances.
- **Nucleated**: Companion cells contain a nucleus, which is essential for their function and maintenance.
- **Narrow Structure**: These cells are narrow in width, allowing them to fit closely with sieve elements.
- **Elongated Shape**: Companion cells are elongated, which helps in their arrangement alongside sieve tubes.

3. **Evaluation of Options**:
- The question likely provides multiple-choice options regarding the properties of companion cells. Each option should be evaluated based on the characteristics listed above.
- For each option, check if it includes the following properties: living, nucleated, narrow, elongated, and involved in transport.

4. **Identifying the Correct Option**:
- After evaluating each option based on the properties of companion cells, identify which option includes all the correct characteristics.
- In this case, the correct option should include: living, nucleated, narrow, elongated, and involved.

5. **Conclusion**: The correct answer is the option that accurately describes all the properties of companion cells. Based on the evaluation, option number 2 is the correct answer.