There are 42 chromosomes in a cell. After a particular phase of mitosis, the number of chromosomes remain same. Name the phase.
I. Anaphase
II. Metaphase
III. Prophase
IV. Telophase

Anaphase of mitosis is marked by splitting of centromere and separation and movement of sister chromatids towards the opposite poles. Splitting of centromere, will cause doubling of the number of chromosomes from 42 to 84 by the end of anaphase. Likewise, telophase of mitosis is marked by the formation of the nuclear membrane around sister chromatids (now called as chromosomes) present at opposite poles. Hence, telophase ends with reducing the number of chromosomes from 42 to 21 in the cell. Metaphase includes movement and arrangement of sister chromatids on the cell’s equator while prophase is marked by the appearance of chromosomes with sister chromatids due to condensation of the chromatin fibre. Hence, metaphase and prophase cell will maintain the same chromosome number i.e., 42.
So, the correct answer is known as option B.