The correct answer is B. Embryonic stem cell research requires the use of human embryos.
Research on human Stem cell greatly helped in understanding basic process of development and differentiation in humans. Human stem cell research also helped in finding new treatments for many diseases such as Parkinson’s disease, injury of spinal cord and diabetes. But at the same time human stem cell research also created some ethical controversies because for the research cells are taken out from oocytes and embryos which is something undesirable. The ethical issues are required to be discussed and stem cell research to be carried out in an appropriate manner.