An organised and differentiated cellular structure having cytoplasm but no nucleus is

Options

A. vessels
B. xylem parenchyma
C. sieve tubes
D. tracheids

Explanation

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for an organized and differentiated cellular structure that has cytoplasm but lacks a nucleus. This indicates we are looking for a specific type of cell or tissue in plants.

2. **Analyzing the Options**: We need to evaluate each option provided to determine which one fits the criteria of having cytoplasm but no nucleus.

3. **Option A - Vessels**:
- Vessels are part of the xylem tissue, which is responsible for the transport of water and minerals in plants.
- Upon examination, xylem vessels do contain nuclei. Therefore, this option is not correct.

4. **Option B - Xylem Parenchyma**:
- Xylem parenchyma is another component of xylem tissue.
- It also contains nuclei, thus making this option incorrect as well.

5. **Option C - Sieve Tubes**:
- Sieve tubes are part of the phloem tissue, which is involved in the transport of sugars and nutrients.
- Sieve tube members are unique because they lack a nucleus. Instead, they rely on companion cells, which do have nuclei, to support their functions. Therefore, this option fits the criteria.

6. **Option D - Tracheids**:
- Tracheids are another component of xylem tissue.
- Similar to vessels and parenchyma, tracheids also contain nuclei, making this option incorrect.

7. **Conclusion**: After evaluating all options, the correct answer is **Option C - Sieve Tubes**, as they are organized structures with cytoplasm but no nucleus.