Asserotion: `C_(4)` photosynthetic pathway is more efficient than the `C_(3)` pathway.
Reson : Photorespirationis suppressed in `C_(4)` plants.

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 solve the assertion and reason question regarding the efficiency of the C4 photosynthetic pathway compared to the C3 pathway, we will break down the information step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that the C4 photosynthetic pathway is more efficient than the C3 pathway.
- This is based on the fact that C4 plants produce a 4-carbon compound as the first stable product of photosynthesis, while C3 plants produce a 3-carbon compound.

2. **Examining the Efficiency**:
- In terms of energy yield, C4 plants generate approximately 30 ATP molecules from one glucose molecule, while C3 plants yield around 18 ATP molecules from the same amount of glucose.
- This indicates that C4 plants have a higher ATP production, which contributes to their efficiency in photosynthesis.

3. **Understanding the Reason**:
- The reason given is that photorespiration is suppressed in C4 plants.
- Photorespiration is a process that can be wasteful because it consumes energy without producing useful products. It occurs when the enzyme RuBisCO fixes oxygen instead of carbon dioxide.

4. **Linking the Reason to the Assertion**:
- C4 plants have adapted to minimize photorespiration, especially in hot and dry environments, which allows them to conserve energy and maintain higher efficiency in photosynthesis.
- By suppressing photorespiration, C4 plants can maximize their ATP production and overall photosynthetic efficiency.

5. **Conclusion**:
- Both the assertion and the reason are true. The reason correctly explains why the C4 pathway is more efficient than the C3 pathway.

### Final Answer:
Both the assertion and reason are true, and the reason is the correct explanation for the assertion.