Ans.
Stem cells are those cells, which have ability to divide and develop into specialized cells in the body. Stem cells can be found in embryo (known as embryonic stem cells and in adults (known as adult stem cells).
Embryonic stem cells are pluoripitent cells having capability to develop into any cell type. Adult stem cells can differentiated into only limited cell types. For example, hematopoetic stem cell that can form only different types of blood cells.
Thus, the correct answer is 'adult stem cells.'