[A]: The evolution of molecular oxygen is con- cerned with photosystem-1 (PSI).
[R]: The photosystem-11 (PS-II) is not involved in the evolution of oxygen.

Options

A. If both A and R are true and R is the correct explanation of A
B. If both A and R are true but R is not the correct explanation of A
C. If A is true and R is false
D. If both A and R are false

Answer

To analyze the assertion and reasoning provided in the question, let's break down the concepts related to photosystems in photosynthesis, particularly focusing on Photosystem I (PSI) and Photosystem II (PSII).

### Step-by-Step Solution:

1. **Understanding Photosystems**:
- Photosynthesis involves two main photosystems: Photosystem I (PSI) and Photosystem II (PSII).
- PSI absorbs light primarily at a wavelength of 700 nm, while PSII absorbs light at a wavelength of 680 nm.

2. **Role of PSII in Oxygen Evolution**:
- The evolution of molecular oxygen (O2) occurs during the light-dependent reactions of photosynthesis, specifically through the process of photolysis of water (H2O).
- PSII is responsible for this process, where water molecules are split to release oxygen, protons, and electrons.

3. **Assertion Analysis**:
- The assertion states that the evolution of molecular oxygen is concerned with PSI. This is incorrect because it is actually PSII that is involved in the release of oxygen during photosynthesis.

4. **Reasoning Analysis**:
- The reasoning states that PSII is not involved in the evolution of oxygen. This is also incorrect, as PSII plays a crucial role in the photolysis of water, leading to the release of O2.

5. **Conclusion**:
- Both the assertion (A) and the reasoning (R) are false. Therefore, the correct answer to the question is that both A and R are false.

### Final Answer:
Both the assertion (A) and reasoning (R) are false.