`PS` II performs

Options

A. Reduction of `CO_(2)`
B. Photolysis of water
C. Liberation of energy
D. Formation of water.

Answer

To solve the question "PS II performs," we need to analyze the options provided and understand the role of Photosystem II (PS II) in the process of photosynthesis.

### Step-by-Step Solution:

1. **Understanding Photosystem II (PS II)**:
- Photosystem II is a crucial component of the photosynthetic process that occurs in the thylakoid membranes of chloroplasts. It is primarily involved in the light-dependent reactions of photosynthesis.

2. **Analyzing the Options**:
- **Reduction of Carbon Dioxide**: This process occurs later in the Calvin cycle and is not directly associated with PS II.
- **Photolysis of Water**: This is the splitting of water molecules into oxygen, protons, and electrons in the presence of light. This process occurs in PS II and is essential for providing electrons to the electron transport chain.
- **Liberation of Energy**: While energy is released during the light-dependent reactions, it is not a direct function of PS II alone.
- **Formation of Water**: This is incorrect as PS II does not produce water; it breaks down water.

3. **Identifying the Correct Answer**:
- The primary function of PS II is the **photolysis of water**. This process generates oxygen as a byproduct and provides electrons that are essential for the continuation of the photosynthetic electron transport chain.

4. **Conclusion**:
- Therefore, the correct answer to the question "PS II performs" is **photolysis of water**.