Which one of the following corresponds for the start of M-phase?

Options

A. A. Cytokinesis
B. B. `G_1` -phase
C. C. Karyokinesis
D. D. Karyogenesis

Explanation

To determine which option corresponds to the start of M-phase, we need to understand the phases of the cell cycle, particularly focusing on M-phase.

### Step-by-Step Solution:

1. **Understanding M-phase**: M-phase, or mitotic phase, is the part of the cell cycle where cell division occurs. It includes two main processes: karyokinesis and cytokinesis.

2. **Identifying the Options**:
- **Cytokinesis**: This is the process of cytoplasmic division that occurs after karyokinesis.
- **G1 Phase**: This is a part of interphase where the cell grows and prepares for DNA replication, not part of M-phase.
- **Karyokinesis**: This is the division of the nucleus and is the first step in M-phase.
- **Cariogenesis**: This term is not commonly used in the context of cell division and may be a misnomer.

3. **Determining the Start of M-phase**: The start of M-phase is marked by the beginning of karyokinesis, where the nucleus divides.

4. **Conclusion**: Therefore, the correct answer is **C. Karyokinesis**.