The scenario that represents mitosis in action is:
C: a skin cell repairing itself after a cut.
Mitosis is the process of cell division that results in two daughter cells, each having the same number of chromosomes as the original cell. This happens in eukaryotic cells (like skin cells) during growth, repair, or replacement. The other options involve processes outside the scope of mitosis: option A refers to binary fission in prokaryotic cells (bacteria), option B involves fertilization (fusion of gametes), and option D does not specifically indicate cell division but rather preparation for enzyme production.