Ribbon-shaped chloroplasts occur in

Options

A. Chlamydomonas
B. Spirogyra
C. Ulothrix
D. Riccia.

Answer

To solve the question "Ribbon-shaped chloroplasts occur in," we will analyze each option provided and identify the correct one.

### Step-by-Step Solution:

1. **Understanding the Question**: We need to identify which organism has ribbon-shaped chloroplasts. Chloroplasts are the organelles in plant cells responsible for photosynthesis, and their shape can vary among different species.

2. **Analyzing the Options**:
- **Option 1: Chlamydomonas**: This organism typically has cup-shaped chloroplasts. Therefore, this option is incorrect.
- **Option 2: Spirogyra**: Spirogyra is known for its spiral-shaped chloroplasts, which can appear ribbon-like due to their elongated structure. This option is a strong candidate.
- **Option 3: Eulothrix**: In Eulothrix, the chloroplasts are generally disc-shaped. Thus, this option is also incorrect.
- **Option 4: Bixia**: The chloroplasts in Bixia exhibit a rosette shape. Therefore, this option is incorrect as well.

3. **Conclusion**: Based on the analysis, the organism with ribbon-shaped chloroplasts is **Spirogyra** (Option 2).

### Final Answer:
The correct answer is **Option 2: Spirogyra**.

---