Why Are Cancer Cells More Sensitive to Radiation Than Normal

Why are cancer cells more sensitive to radiation than normal cells?

A) The cells most sensitive to radiation are the ones undergoing rapid cellular division; cancer cells are an example of rapidly dividing cells.
B) The cells most sensitive to radiation are the ones undergoing slow cellular division; cancer cells are an example of slowly dividing cells.
C) The cells most sensitive to radiation are the ones that do not undergo cellular division; cancer cells are an example of cells that do not divide.
D) Cancer cells generally form on top of normal cells; they are therefore the cells closest to the applied radiation.
E) Cancer cells are shielded from radiation by their thick cellular membrane; normal cells lack this cellular membrane.