An individual bathing in an infected pool or coming in contact with contaminated water is liable to be infected with____. The ____larva stick to the surface of the skin of swimmer or bather, and penetrate the skin.
1) Ancylostoma, I I n d juvenile
2) Bilharzia, Cercaria
3) Schistosoma, metacercariae
4)Bilharzia, redia

Options

A. Ancylostoma, `II^(nd)` juvenile
B. Bilharzia, Cercaria
C. Schistosoma, metacercariae
D. Bilharzia, redia

Explanation

To solve the question, we need to identify the correct disease and the larval stage associated with an individual bathing in an infected pool or coming into contact with contaminated water.

### Step-by-Step Solution:

1. **Understanding the Question**: The question states that an individual bathing in an infected pool or contaminated water can be infected by a certain organism, and we need to fill in the blanks with the correct disease and larval stage.

2. **Identifying the Disease**: The term "Bilharzia" refers to schistosomiasis, which is caused by the genus Schistosoma. This disease is commonly associated with freshwater environments where people may come into contact with contaminated water.

3. **Identifying the Larval Stage**: The larval stage that is known to penetrate the skin of swimmers is called "cercaria." This is the infective form of the larva that emerges from the snail host and can penetrate human skin.

4. **Evaluating the Options**:
- **Option 1**: Ancylostoma, Juvenile - This does not relate to the context of swimming in contaminated water.
- **Option 2**: Bilharzia, Cercaria - This matches our findings as Bilharzia refers to schistosomiasis and cercaria is the larval stage that penetrates the skin.
- **Option 3**: Schistosoma, Metacercariae - Metacercariae is not the correct larval stage for Schistosoma; it is associated with other parasites.
- **Option 4**: Bilharzia, Redia - Redia is a larval stage associated with different life cycles and does not penetrate human skin.

5. **Conclusion**: The correct answer is **Option 2: Bilharzia, Cercaria**.

### Final Answer:
**Option 2: Bilharzia, Cercaria**