
Passage: A new medical technology can be used clinically only if it is effective and safe. In 1998, American scientists successfully made human embryonic stem cells grow and proliferate in vitro. if this stem cell technology is combined with cloning technology, the necessary tissue cells can be cultured from patients' somatic cells to replace patients' damaged cells. to treat a variety of difficult diseases, this is the so-called "therapeutic cloning". But now "therapeutic cloning" is still a long way from clinical use.
Question: Which of the followings, if true, will give the above conclusion the strongest support?
A. A.Because "therapeutic cloning" involves the destruction of early human embryos, it has aroused strong opposition from the Roman Church and the governments of the United States, France, Germany and other countries
B. B.So far, it is quite difficult to obtain human embryonic stem cells
C. C.Hwang Woo-suk, a South Korean scholar, has promised to repair stem cells for a child paralyzed by a car accident, but all of his stem cell research results are fake
D. D.At present, scientists are far from understanding the mechanism by which human embryonic stem cells differentiate into various cells and how to prevent them from turning into cancer cells
Answer: