Answer: The correct answer is -
Special cells taken from the human umbilical cord.
Step-by-step explanation:
Stem cell can be described as an undifferentiated cell (that is without being specialised) of a multicellular organism that has potential of giving more cells of the same kind through proliferation, and from which ultimately specialised cells (such as muscle cells, nerve cells, blood cells) are produced through the process of differentiation.
They are present in embryonic (particularly in inner cell mass) as well as adult stage (such as in blood, bone marrow, and adipose tissue) of an individual.
Blood from the human Umbilical cord during birth is a good source of stem cells, which is also used in research and in the treatment of diseases.
Thus, first option is the right answer.