Assertion : Artificial kidney operates on the principle of haemodialysis.
Reason : Artificial kidneys involve both passive and active processes.

Options

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

Answer

To solve the question, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Artificial kidney operates on the principle of haemodialysis."
- This is true because artificial kidneys (dialysis machines) do indeed function by the process of haemodialysis, which is a method used to remove waste products and excess fluid from the blood when the kidneys are not functioning properly.

2. **Understanding the Reason**:
- The reason states that "Artificial kidneys involve both passive and active processes."
- This statement is somewhat misleading. While haemodialysis primarily relies on passive diffusion (the movement of solutes from an area of higher concentration to an area of lower concentration), it does not typically involve active transport processes, which require energy. Therefore, this statement is false.

3. **Evaluating the Relationship**:
- The assertion is true, but the reason is false.
- Since the reason does not correctly explain the assertion, we conclude that the correct answer is that both the assertion is true, and the reason is false.

### Conclusion:
The correct answer is: **Assertion is true but Reason is false.**