Assertion. In light reaction of photosynthesis, light is required for the functioning of PS I and PS II and Production of NADPH and ATP.
Reason. Dark reaction does not occur in light.

Options

A. If both the with reason being correct explanation
B. both true but reason is not correct explanation
C. assertion is true but reason is wrong
D. both are wrong.

Answer

### Step-by-Step Solution

1. **Understanding the Assertion**: The assertion states that in the light reaction of photosynthesis, light is essential for the functioning of Photosystem I (PS I) and Photosystem II (PS II), as well as for the production of NADPH and ATP. This is true because light energy is required to excite electrons in these photosystems, which initiates the process of photosynthesis.

2. **Explaining the Light Reaction**: During the light reaction, when light is absorbed by PS II, it excites electrons, which are then transferred through a series of proteins (the electron transport chain). This process leads to the production of ATP through photophosphorylation and the reduction of NADP+ to NADPH. Both ATP and NADPH are crucial for the subsequent dark reactions.

3. **Understanding the Reason**: The reason provided states that the dark reaction does not occur in light. This statement is incorrect. The dark reactions (Calvin cycle) can occur in both light and dark conditions as long as the necessary products (ATP and NADPH) from the light reactions are available.

4. **Conclusion**: Therefore, the assertion is true while the reason is false. The correct answer is that the assertion is true and the reason is false.

### Final Answer
- Assertion: True
- Reason: False
- Correct Option: Assertion is true, Reason is false.