Assertion : Chloride shift is exchange of `Cl^(-)` of plasma and `HCO_(3)^(-)` of RBCs.
Reason Chloride shift, maintains an acid base balance between the RBC's and plasma.

Options

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

Explanation

### Step-by-Step Solution:

1. **Understanding the Assertion**: The assertion states that the chloride shift involves the exchange of chloride ions (Cl^(-)) from plasma with bicarbonate ions (HCO3^(-)) from red blood cells (RBCs).

2. **Mechanism of Chloride Shift**: In the RBCs, carbon dioxide (CO2) and water (H2O) react to form carbonic acid (H2CO3). This carbonic acid then dissociates into bicarbonate ions (HCO3^(-)) and hydrogen ions (H^+).

3. **Movement of Ions**: The bicarbonate ions (HCO3^(-)) diffuse out of the RBCs into the plasma. Since the RBCs now have a higher concentration of positive hydrogen ions (H^+), this creates a net positive charge inside the RBCs.

4. **Compensatory Mechanism**: To balance the positive charge inside the RBCs, chloride ions (Cl^(-)) from the plasma move into the RBCs. This exchange of ions is what is referred to as the chloride shift.

5. **Conclusion on Assertion**: Therefore, the assertion is correct as it accurately describes the exchange of Cl^(-) and HCO3^(-) during the chloride shift.

6. **Understanding the Reason**: The reason states that the chloride shift maintains an acid-base balance between the RBCs and plasma.

7. **Acid-Base Balance**: The movement of bicarbonate ions out of the RBCs and chloride ions into the RBCs helps to neutralize the charges and maintain the pH balance, which is crucial for proper physiological function.

8. **Conclusion on Reason**: Thus, the reason is also correct as it explains the function of the chloride shift in maintaining acid-base balance.

9. **Final Evaluation**: Both the assertion and the reason are correct, and the reason provides a correct explanation for the assertion.

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

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