Select the option that is correct with respect to Trypanosoma.

Options

A. They are flagellated protozoans.
B. They are parasites.
C. They cause sleeping sickness.
D. All of the above

Answer

To solve the question regarding Trypanosoma, we will analyze each option provided and determine which statements are correct.

### Step-by-Step Solution:

1. **Understanding Trypanosoma**:
- Trypanosoma is a genus of protozoan parasites. They are known for their flagellated structure which aids in their movement.

2. **Analyzing the Options**:
- **Option 1: They are flagellated protozoans**:
- This statement is correct. Trypanosoma species possess a flagellum that helps them move.

- **Option 2: They are parasites**:
- This statement is also correct. Trypanosoma is known to be a parasitic organism, living in the host and deriving nutrients at the host's expense.

- **Option 3: They cause sleeping sickness**:
- This statement is correct as well. Trypanosoma brucei, in particular, is responsible for causing sleeping sickness (also known as human trypanosomiasis).

3. **Final Evaluation**:
- Since all the individual statements about Trypanosoma are correct, we can conclude that the correct answer is **"all of the above"**.

### Conclusion:
The correct option with respect to Trypanosoma is **"all of the above"**.