Free swimming ciliated stage of liver fluke is

Options

A. Redia
B. Miracidium
C. Metacercaria
D. Cercaria

Explanation

To answer the question regarding the free swimming ciliated stage of the liver fluke, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Organism**: The liver fluke is a parasitic flatworm belonging to the class Trematoda. It has a complex life cycle involving multiple stages and hosts.

2. **Understand the Life Cycle**: The liver fluke undergoes several developmental stages, including eggs, larvae, and adult forms. The life cycle typically involves a definitive host (usually a mammal) and one or more intermediate hosts (often snails).

3. **Focus on the Ciliated Stage**: The question specifically asks for the free swimming ciliated stage. In the life cycle of liver flukes, the first larval stage that is free-swimming and possesses cilia is known as the **miracidium**.

4. **Examine the Options**: The options given are:
- A) Radia
- B) Miracidium
- C) Metacercaria
- D) Cercaria

- **Radia**: This is not a recognized stage in the liver fluke life cycle.
- **Miracidium**: This is the correct answer, as it is the free-swimming ciliated larva that emerges from the egg.
- **Metacercaria**: This stage is not free-swimming; it is a dormant stage encysted in the host.
- **Cercaria**: This stage is also not the initial free-swimming ciliated stage; it is a later stage that emerges from the snail.

5. **Conclude the Answer**: Based on the information, the correct answer to the question is **Miracidium**.

### Final Answer:
The free swimming ciliated stage of the liver fluke is **Miracidium**.