An angiosperm having monarch xylem is

Options

A. casuarina
B. Trapa
C. strychnos
D. Urtica

Answer

### Step-by-Step Solution

1. **Understanding Monarch Xylem**:
- Monarch xylem is a specific arrangement of xylem found in certain plants. It typically refers to a single strand of xylem that is centrally located within the vascular system of the plant.

2. **Identifying Key Characteristics**:
- Monarch xylem is characterized by having a central vascular cylinder, which is referred to as a "stele." This arrangement is commonly found in plants with assimilatory submerged roots and spongy petioles.

3. **Analyzing the Options**:
- The options given are:
1. Casuarina
2. Trepa
3. Strychnos
4. Urtica

4. **Evaluating Each Option**:
- **Casuarina**: This plant does not exhibit monarch xylem.
- **Trepa**: This plant is known to have monarch xylem, fitting the description of having a single xylem strand and a central vascular cylinder.
- **Strychnos**: This plant does not have monarch xylem.
- **Urtica**: This plant also does not exhibit monarch xylem.

5. **Conclusion**:
- Based on the characteristics of monarch xylem and the evaluation of the options, the correct answer is **Trepa**.

### Final Answer
An angiosperm having monarch xylem is **Trepa**.

---