Which one of the following is a rootless aquatic herb where a portion of leaf forms a small bladder that traps small insects ?

Options

A. Dionaea
B. Nepenthes
C. Utricularia
D. Drosera

Explanation

To solve the question, "Which one of the following is a rootless aquatic herb where a portion of leaf forms a small bladder that traps small insects?" we will analyze the options provided and identify the correct answer step by step.

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for a specific type of plant that is both rootless and aquatic, and has a unique feature of trapping insects using a part of its leaf that forms a small bladder.

2. **Analyze the Options**:
- **Dionea (Venus Flytrap)**: This plant is known for trapping insects using modified leaves that snap shut when prey touches sensitive hairs. However, it is not aquatic and does not have bladders.
- **Nepenthes (Pitcher Plant)**: This plant has a pitcher-shaped structure that traps insects using a slippery surface. It is not rootless and is typically not aquatic.
- **Eutrichilaria**: This is a rootless aquatic herb that has specialized structures (bladders) to trap small aquatic insects. It is known for its carnivorous nature and suction traps.
- **Drosera (Sundew)**: This plant traps insects using glandular hairs that secrete sticky substances. It is not rootless and does not have bladders.

3. **Identify the Correct Answer**: Based on the analysis, the only option that fits all the criteria of being a rootless aquatic herb with bladders that trap insects is **Eutrichilaria**.

### Final Answer:
The correct answer is **Eutrichilaria**.