Which out of the following does not belong to brown algae

Options

A. Gelidium,Batrachospermum
B. Ectocarpus,dictyota
C. Laminaria,fucus
D. Sargassum, ectocarpus

Explanation

To determine which of the given options does not belong to brown algae, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Identify the Options**:
- Option 1: Gelidium and Batrachospermum
- Option 2: Ectocarpus and Dictyota
- Option 3: Laminaria and Fucus
- Option 4: Sargassum and Ectocarpus

2. **Analyze Option 1 (Gelidium and Batrachospermum)**:
- Both Gelidium and Batrachospermum are identified as red algae.
- Gelidium belongs to the class Rhodophyceae and has around 124 species.
- Batrachospermum is a freshwater red algae found in lakes and rivers.
- **Conclusion**: This option does not belong to brown algae.

3. **Analyze Option 2 (Ectocarpus and Dictyota)**:
- Both Ectocarpus and Dictyota are classified as brown algae.
- Ectocarpus is a branched filamentous algae.
- Dictyota is a seaweed that falls under the family Pheophyceae.
- **Conclusion**: This option belongs to brown algae.

4. **Analyze Option 3 (Laminaria and Fucus)**:
- Laminaria and Fucus are both brown algae.
- Laminaria is commonly known as kelp and has around 31 species.
- Fucus is found in intertidal zones.
- **Conclusion**: This option belongs to brown algae.

5. **Analyze Option 4 (Sargassum and Ectocarpus)**:
- Both Sargassum and Ectocarpus are also classified as brown algae.
- They are filamentous forms of algae.
- **Conclusion**: This option belongs to brown algae.

### Final Conclusion:
- The only option that does not belong to brown algae is **Option 1: Gelidium and Batrachospermum**, as both of these are red algae.