An enterocoelomate invertebrate group is

Options

A. Annelida
B. Echinodermate
C. Arthropoda
D. Mollusca.

Answer

To determine which of the given invertebrate groups is classified as enterocoelomate, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Coelom**:
- Coelom refers to the body cavity found within organisms. It is important to know that there are different types of coelomates based on how the body cavity is formed during embryonic development.

2. **Identify Types of Coelomates**:
- There are two main types of coelomates:
- **Schizocoelomate**: Where the coelom forms from the splitting of the mesoderm.
- **Enterocoelomate**: Where the coelom forms from outpocketings of the embryonic gut (endoderm).

3. **Analyze the Given Options**:
- The options provided are:
- A) Annelida
- B) Echinodermata
- C) Arthropoda
- D) Mollusca

4. **Classify Each Group**:
- **Annelida**: Schizocoelomate (coelom forms from mesodermal split).
- **Echinodermata**: Enterocoelomate (coelom forms from outpocketings of the gut).
- **Arthropoda**: Schizocoelomate (coelom forms from mesodermal split).
- **Mollusca**: Schizocoelomate (coelom forms from mesodermal split).

5. **Select the Correct Answer**:
- Based on the classification, the only group that is enterocoelomate from the options provided is **Echinodermata**.

### Final Answer:
The enterocoelomate invertebrate group is **Echinodermata**.