Which one of the following pair is correctly matched?

Options

A. Shortest phase of cell cycle - M- phase
B. Synthesis of histone protein - `G2phase
C. DNA replication - `G_(1)`-phase
D. Synthesis of RNA and protein - M-phase

Explanation

To determine which pair is correctly matched, we need to analyze each of the provided options regarding the phases of the cell cycle.

### Step-by-Step Solution:

1. **Identify the Phases of the Cell Cycle**:
- The cell cycle consists of two main phases: Interphase and M phase (Mitosis).
- Interphase is further divided into three sub-phases: G1 phase, S phase, and G2 phase.

2. **Evaluate Option 1**:
- "Shortest phase of cell cycle is M phase."
- The M phase (Mitosis) is indeed the shortest phase of the cell cycle. This statement is **correct**.

3. **Evaluate Option 2**:
- "The synthesis of histone protein takes place in G2 phase."
- Histone proteins are synthesized during the S phase when DNA replication occurs, not in the G2 phase. This statement is **incorrect**.

4. **Evaluate Option 3**:
- "DNA replication takes place in G1 phase."
- DNA replication occurs during the S phase, not in the G1 phase. This statement is **incorrect**.

5. **Evaluate Option 4**:
- "Synthesis of RNA and protein takes place in the M phase."
- RNA and protein synthesis primarily occurs during the interphase, particularly in the G1 and G2 phases. This statement is **incorrect**.

6. **Conclusion**:
- The only correct option is Option 1: "Shortest phase of cell cycle is M phase."

### Final Answer:
The correctly matched pair is **Option 1**: Shortest phase of the cell cycle is M phase.

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