Answer:
Option B.
Disappearance of nuclear memberane.
Explanation:
This is because Prophase is marks the beginning of mitosis, and it is the process where replicated genetic contents are separated into daughter cells. During prophase, ttgere is condensation of chromatin. The chromatin coils and it become compact, which lead to the formation o chromosomes that are visible. The sister chromatids are joined together at the centromere. The mitotic spindle begins to form. The mitotic spindle is consist of long proteins called microtubules that firms at opposite end. The spindle separate the two sister chromatids.
