According to the law of Bergonié and Tribondeau, when are cells most sensitive to radiation?

The law of Bergonié and Tribondeau states that the sensitivity of cells to radiation is closely related to their stage of development and division rate. Cells that are immature, undifferentiated, and rapidly dividing are more susceptible to the effects of radiation. This is because these cells are in phases of the cell cycle where they are actively replicating their DNA and undergoing cell division, making them more vulnerable to the damaging effects of radiation, which can interfere with these critical processes.

In contrast, mature and differentiated cells tend to be more stable and are often in a quiescent state, meaning they are not actively dividing, which makes them less sensitive to radiation. Dormant or stable cells are in a phase where they do not engage in replication, leading to reduced radiation sensitivity as there is limited activity to disrupt. Fully differentiated and functional cells are typically specialized and have lost their capacity to divide, thereby lessening their susceptibility to radiation damage. Therefore, the correct choice reflects the principle that immature, undifferentiated, and rapidly dividing cells carry the greatest risk from radiation exposure.