Compared to differentiated cells, stem cells have a longer interphase. Three different human alveolar cell-types (stem cells, normal cells and cancer cells) grown under optimal laboratory conditions were examined microscopically (Figure). The nucleus was stained blue and phos-H2A.X protein green. Phos-H2A.X is found only at damaged DNA site in vivo. Each green dot is considered as an event of DNA damage or a cluster of events called foci. Based on the comparison of the results between these three cell types, choose the correct option(s).

• A

  Although carcinogens damage DNA, cellular processes do not lead to such damages.
• Correct answer
  B

  The rate of cell division can be directly correlated to the number of DNA breaks.
• C

  The experiment clearly indicates that the M-phase of the three cell types is different.
• D

  The rate of DNA damage is inversely proportional to its occurrence in cancer cells.

Hence, the correct answer is option: 'B'.