In which phase of mitosis do the nuclear membrane and nucleolus start to disappear while centrioles duplicate and move to opposite poles?

1. In prophase the thin chromosomes condense and become short and thick with sister chromatids. 2. Centrioles duplicate and each moves to opposite poles. 3. The nuclear membrane and nucleolus start to disappear in this phase. 4. In metaphase the nuclear membrane has already completely disappeared, so it is ruled out. 5. In telophase the nuclear membrane reforms instead of disappearing, so it is ruled out. 6. In anaphase centromeres split and chromatids separate, which is a different event, so it is ruled out. _Source: Balbharati (Maharashtra Board) Class 10 Science & Technology Part 2, Ch 2 "Life Processes in Living Organisms Part 1", p.27_