Assertion: Assimilotary power in photosynthesis is generated in ETS occuring in thylakoid membrane .
Reason : They are needed for `CO_(2)` reduction.

Options

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

Answer

**Step-by-Step Solution:**

1. **Understanding the Assertion**: The assertion states that "assimilatory power in photosynthesis is generated in the electron transport system (ETS) occurring in the thylakoid membrane." This means that the energy carriers ATP and NADPH, which are crucial for photosynthesis, are produced during the light-dependent reactions that take place in the thylakoid membranes of chloroplasts.

2. **Understanding the Reason**: The reason given is that "they are needed for CO₂ reduction." This indicates that ATP and NADPH produced in the light reactions are essential for the Calvin cycle, where carbon dioxide is converted into glucose.

3. **Evaluating the Assertion**: The assertion is true because the electron transport chain in the thylakoid membrane indeed generates ATP and NADPH during the light-dependent reactions of photosynthesis.

4. **Evaluating the Reason**: The reason is also true because ATP provides the energy, and NADPH provides the reducing power necessary for the conversion of carbon dioxide into glucose in the Calvin cycle.

5. **Determining the Relationship**: While both the assertion and the reason are true, the reason does not explain why the assimilatory power is generated in the ETS. The assertion focuses on the location and process of ATP and NADPH production, while the reason discusses their role in a subsequent process.

6. **Conclusion**: Both the assertion and the reason are true, but the reason is not the correct explanation of the assertion. Therefore, the final answer is that both statements are true, but the reason does not correctly explain the assertion.