Ans.
Stem cells are defined as cells that have ability to develop into different types of body cells. Stem cells undergo differentiation, a process in which one cell changes into another kind of cell, to form different types of specified cells from a single, unspecified, parent stem cell.
For example, a single hematopoetic stem cell differentiates to produce all kinds blood cells, such as red blood cells, white blood cells, and platelets.
Thus, the correct answer is 'option). differentiation.'