Guard cells :
a. Enclose stomatal pore
b. Are dumb - bell shaped in dicots
c. Outer wall thick and inner wall thin
d. Regulates opening and closing of stomata

Options

A. a & b are correct
B. a & d are incorrect
C. b & c are incorrect
D. c & d are correct

Answer

To analyze the statements regarding guard cells, we will evaluate each statement one by one based on the information provided in the video transcript.

### Step-by-Step Solution:

1. **Statement A: Enclose stomatal pore**
- **Evaluation**: Guard cells indeed enclose the stomatal pore, which is the opening that allows gas exchange in plants.
- **Conclusion**: This statement is **correct**.

2. **Statement B: Are dumb-bell shaped in dicots**
- **Evaluation**: The transcript states that guard cells in dicots are bean-shaped, while in monocots, they are dumbbell-shaped.
- **Conclusion**: This statement is **incorrect**.

3. **Statement C: Outer wall thick and inner wall thin**
- **Evaluation**: According to the transcript, the outer wall of guard cells is thin, and the inner wall is thickened.
- **Conclusion**: This statement is **incorrect**.

4. **Statement D: Regulates opening and closing of stomata**
- **Evaluation**: The transcript confirms that guard cells are responsible for regulating the opening and closing of stomata.
- **Conclusion**: This statement is **correct**.

### Summary of Evaluations:
- Statement A: Correct
- Statement B: Incorrect
- Statement C: Incorrect
- Statement D: Correct

### Final Conclusion:
The correct statements are A and D, while B and C are incorrect. Therefore, the correct answer is that **B and C are incorrect**.