Which of the following have internal fertilization?

Options

A. Sea urchin
B. Platypus
C. Frog
D. Labeo

Answer

To determine which of the given organisms undergoes internal fertilization, we can analyze each option based on their reproductive methods.

### Step-by-Step Solution:

1. **Understanding Internal Fertilization**:
- Internal fertilization occurs when the male gamete (sperm) fertilizes the female gamete (egg) inside the female's body. This is different from external fertilization where fertilization occurs outside the female's body, typically in water.

2. **Analyzing the Options**:
- **Option A: Sea Urchin**: Sea urchins reproduce through external fertilization. They release their gametes into the water where fertilization occurs.
- **Option B: Platypus**: The platypus is a unique mammal that lays eggs and has internal fertilization. The male fertilizes the female's eggs inside her body before she lays them.
- **Option C: Frog**: Frogs also reproduce through external fertilization. The male frog releases sperm over the eggs as the female lays them in water.
- **Option D: Labia**: This option seems to be a typographical error or misinterpretation. If it refers to a specific organism, clarification is needed, but generally, many organisms in this category also reproduce externally.

3. **Conclusion**:
- Among the options provided, the only organism that has internal fertilization is the **platypus** (Option B).

### Final Answer:
**B. Platypus**

---