[单项选择]Passage 3 Human cloning technology could be used to reverse heart attacks. Scientists believe that they may be able to treat heart attack victims by cloning their healthy heart cells and injecting them into the areas of the heart that have been damaged, and other problems may be solved if human cloning and its technology are not forbidden. With cloning, infertile couples could have children. Current treatments for infertility, in terms of percentages, are not very successfully. Couples go through physically and emotionally painful procedures for a small chance of having children. Many couples run out of time and money without successfully having children. Human cloning could make it possible for many more infertile couples to have children than ever before. We should be able to clone the bone marrow for children and adults suffering from leukemia. This is expected to be one of the first benefits to come from cloning technology. We may learn how to switch
A. removing the damaged part of the heart
B. replacing the old heart with a cloned one
C. repairing the heart with cells cloned from healthy ones
D. giving the patients injections of various medicines