The cells which are devoid of protoplasm are :

Options

A. Tracheids
B. Vessels
C. Xylem fibres
D. All

Answer

### Step-by-Step Solution:

1. **Understanding Protoplast**:
- Protoplast refers to the living part of a cell, which includes the cytoplasm, organelles, and the nucleus. It is the essential component that maintains the life processes of the cell.

2. **Identifying Dead Cells**:
- Cells that are devoid of protoplast are considered dead cells. These cells do not have the living components necessary for metabolic activities.

3. **Analyzing the Options**:
- The question provides options, and we need to identify which of these are cells devoid of protoplast.

4. **Reviewing Xylem Components**:
- **Tracheids**: These are water-conducting cells in the xylem and are known to be dead cells as they lack protoplast.
- **Vessels**: Similar to tracheids, vessels are also part of the xylem and serve the function of water transport. They are also dead cells and devoid of protoplast.
- **Xylem Fibers**: These provide structural support and are also dead cells, lacking protoplast.
- **Xylem Parenchyma**: This is the only living cell type in the xylem that contains protoplast.

5. **Conclusion**:
- Since tracheids, vessels, and xylem fibers are all dead cells devoid of protoplast, the correct answer to the question is that these cells are indeed the ones that fit the criteria.

### Final Answer:
The cells which are devoid of protoplast are: **Tracheids, Vessels, and Xylem Fibers**.