Assertion: In `C_(4)` plants, photorespiration does not occurs.
Reason: `C_(4)` plants have a mechanism that increaes the concentration of `CO_(2)` at the enzyme site.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Assertion**: The assertion states that in C4 plants, photorespiration does not occur. Photorespiration is a process that can waste energy and carbon by releasing CO2 instead of fixing it into sugars.

2. **Understanding C4 Plants**: C4 plants have a specialized mechanism for photosynthesis that allows them to efficiently fix CO2. They utilize a different pathway involving the enzyme PEP carboxylase, which has a higher affinity for CO2 compared to the enzyme RuBisCO found in C3 plants.

3. **Mechanism of C4 Plants**: The reason given states that C4 plants have a mechanism that increases the concentration of CO2 at the enzyme site. This is true because C4 plants initially fix CO2 into a four-carbon compound, which is then converted to a three-carbon compound in the Calvin cycle. This process effectively concentrates CO2 around RuBisCO, minimizing the chances of photorespiration.

4. **Conclusion on Assertion and Reason**: Since C4 plants have a mechanism that prevents photorespiration by ensuring a higher concentration of CO2 at the enzyme site, both the assertion and the reason are correct. Furthermore, the reason correctly explains why photorespiration does not occur in C4 plants.

5. **Final Answer**: Therefore, the correct option is that both the assertion and the reason are correct, and the reason is a correct explanation for the assertion.

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