According to the cancer stem-cell model for tumor growth and propagation, …

A) transit amplifying cells are incapable of cell division, which is reserved for the cancer stem cells.
B) transit amplifying cells constitute the great majority of the cells in the tumor.
C) if each stem cell divides to create one stem cell and one transit amplifying cell, the abundance of stem cells in the tumor will increase exponentially over time.
D) tumors are genetically heterogeneous, even though they show high phenotypic homogeneity.
E) the transit amplifying cells, even though each acts transiently, carry the whole responsibility for maintenance of the tumor in the long term.