External fertilisation occurs in which of the following pairs of animals ?

Options

A. Hyla and Psittacula
B. Ichthyphis and Pristis
C. Labeo and Rana
D. Scoliodon and Exocoetus

Answer

To determine which pair of animals exhibits external fertilization, we need to analyze the options provided based on our understanding of fertilization methods in different animal groups.

### Step-by-Step Solution:

1. **Understanding External Fertilization**:
- External fertilization occurs when the sperm and egg unite outside the female's body. This is common in aquatic animals, particularly in many fish and amphibians.

2. **Reviewing the Options**:
- We have four pairs of animals to evaluate.

3. **Analyzing Option 1: Hyla and Citakulla**:
- **Hyla**: This is a genus of frogs (amphibians) that typically reproduce through external fertilization.
- **Citakulla**: This is a bird. Birds generally exhibit internal fertilization.
- **Conclusion**: This pair does not exhibit external fertilization.

4. **Analyzing Option 2: Itchiofase and Priestess**:
- **Itchiofase**: This is an amphibian, which usually has external fertilization.
- **Priestess**: This refers to a type of shark (cartilaginous fish), which typically has internal fertilization.
- **Conclusion**: This pair does not exhibit external fertilization.

5. **Analyzing Option 3: Labio and Rana**:
- **Labio**: This refers to a fish (Labio rohita), which generally reproduces through external fertilization.
- **Rana**: This is a genus of frogs (amphibians), which also typically reproduce through external fertilization.
- **Conclusion**: This pair exhibits external fertilization.

6. **Analyzing Option 4: Scoliodon and Exocoetus**:
- **Scoliodon**: This is a type of shark (cartilaginous fish), which usually has internal fertilization.
- **Exocoetus**: This is a flying fish, which typically reproduces through external fertilization.
- **Conclusion**: This pair does not exhibit external fertilization.

7. **Final Conclusion**:
- The only pair that shows external fertilization is **Labio (fish) and Rana (frog)**.

### Answer:
The correct pair of animals that exhibit external fertilization is **Labio and Rana**.