Assertion: `G_(1)` phase is the interval between mitosis and initiation of DNA replication.
Reason: The cell is metabolically inactive druing `G_(1)` phase.

Options

A. If both assertion and reason are true and reason is the correct explantion of assertion
B. If both assertion and reason are true but reason is not the correct explnantion 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 G1 phase is the interval between mitosis and the initiation of DNA replication.
- **Explanation**: The G1 phase (Gap 1 phase) is indeed the first phase of the interphase in the cell cycle that occurs after mitosis (M phase) and before the S phase (Synthesis phase) where DNA replication occurs. Thus, this assertion is **true**.

2. **Understanding the Reason**: The reason provided is that the cell is metabolically inactive during the G1 phase.
- **Explanation**: This statement is **false**. The G1 phase is characterized by active metabolism. During this phase, the cell grows, synthesizes proteins, and prepares for DNA replication. Therefore, the cell is metabolically active during G1.

3. **Evaluating the Relationship**: Now, we need to evaluate the relationship between the assertion and the reason.
- The assertion is true, while the reason is false. This means that the reason does not provide a correct explanation for the assertion.

4. **Conclusion**: Based on the evaluation, the correct answer is that the assertion is true, but the reason is false. Thus, the correct option is C: "Assertion is true but reason is false."