What occurs during telophase of mitosis?

During telophase of mitosis, one of the key events is the reformation of the nuclear envelope around each set of separated chromosomes. This process marks the near end of mitosis, where the chromosomes, having been pulled to opposite ends of the dividing cell, begin to de-condense back into a more relaxed state. As the nuclear envelope re-forms, it encapsulates these chromosomes in two distinct nuclei, effectively creating two daughter nuclei within one cell. This is a crucial step in ensuring that each daughter cell will have its own complete set of genetic material as the process of cell division progresses to cytokinesis.

The other choices describe different stages or processes that do not occur during telophase. Chromosomes condensing into chromatids, for example, is characteristic of prophase, while alignment at the metaphase plate occurs during metaphase itself. Cell elongation is a general feature observed as cells prepare for division but is not specifically attributed to telophase. Thus, the reformation of the nuclear envelope is the defining event that indicates the completion of mitotic division of the nucleus.