Failure of chromatids to segregate during cell division cycle results in:

The correct option is Aneuploidy.

During the normal cell division cycle (mitosis or meiosis), sister chromatids or homologous chromosomes must segregate (separate) equally and move to opposite poles of the spindle apparatus. This ensuring that each daughter cell receives the correct, standard complement of chromosomes.

When chromatids fail to segregate properly—a phenomenon known as nondisjunction—one daughter cell receives an extra chromosome while the other daughter cell lacks that chromosome. This failure leads to an abnormal number of chromosomes in the resulting cells.

Aneuploidy is defined as the condition of having an abnormal number of chromosomes in a cell, which is not an exact multiple of the haploid set (such as having $2n+1$ or $2n-1$ chromosomes). Therefore, the failure of chromatids to segregate during cell division results in aneuploidy.