Bipinnaria is the larval stage of

Options

A. Asterians
B. Echinus (Sea urchin)
C. Anterdorn
D. Cucumaria

Explanation

To solve the question "Bipinnaria is the larval stage of," we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Term**: Understand what "Bipinnaria" refers to. It is a specific type of larval stage.

**Hint**: Look for biological terms that indicate developmental stages in organisms.

2. **Know the Context**: Recognize that "Bipinnaria" is associated with certain marine organisms. This will help narrow down the options.

**Hint**: Consider the groups of animals that have distinct larval stages.

3. **Review the Options**: The options provided are Asterians, Echinus, Antedon, and Cucumeria.

**Hint**: Familiarize yourself with the classifications of these organisms.

4. **Classify the Organisms**:
- **Asterians**: This refers to members of the class Asteroidea, which includes starfish.
- **Echinus**: This is a genus of sea urchins, belonging to a different class (Echinoidea).
- **Antedon**: This refers to crinoids, which belong to the class Crinoidea.
- **Cucumeria**: This is associated with holothurians, which belong to the class Holothuroidea.

**Hint**: Identify which of these classes is known for having the Bipinnaria larval stage.

5. **Determine the Correct Answer**: Since Bipinnaria is the larval stage of organisms in the class Asteroidea, the correct answer is **Asterians**.

**Hint**: Confirm that the larval stage corresponds to the correct class of organisms.

### Final Answer:
Bipinnaria is the larval stage of **Asterians** (class Asteroidea).