Oxygenic photosynthesis occurs in
(a) Chlorobium
(b) Chromatium
(c) Oscillatoria
(d) Rhodospirillum

Options

A. Chlorobium
B. Chromatium
C. Oscillatoria
D. Rhodospirillum

Answer

To solve the question regarding where oxygenic photosynthesis occurs, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Oxygenic Photosynthesis**:
- Oxygenic photosynthesis is a process where water (H2O) acts as an electron donor. During this process, oxygen (O2) is produced as a byproduct.

2. **Identify the Organisms Listed**:
- The options provided are:
- (a) Chlorobium
- (b) Chromatium
- (c) Oscillatoria
- (d) Rhodospirillum

3. **Determine Which Organisms Perform Oxygenic Photosynthesis**:
- **Chlorobium**: This is a green sulfur bacterium that performs anoxygenic photosynthesis, using substances other than water.
- **Chromatium**: This is also a green sulfur bacterium and performs anoxygenic photosynthesis.
- **Oscillatoria**: This is a cyanobacterium, which is known to perform oxygenic photosynthesis.
- **Rhodospirillum**: This is a purple non-sulfur bacterium that performs anoxygenic photosynthesis.

4. **Select the Correct Answer**:
- Among the options, **Oscillatoria** is the only organism that performs oxygenic photosynthesis.

5. **Conclusion**:
- Therefore, the correct answer is **(c) Oscillatoria**.