Answer:
The correct answer is prophase.
Explanation:
Prophase is the first stage of the M-phase that is mitosis and meiosis. In this stage chromatin condenses into chromosomes followed by the nuclear envelope breaks down. This is the first stage where chromosomes are visible. Centriole separation takes place after the nuclear envelope breaks down, and a formation of spindle initiate in prophase.
Thus, the correct answer is prophase.
