To prevent infection, doctors give anti-retroviral drugs (抗逆转录病毒药) to both mothers and their babies, that has greatly reduced the number of infections. But experts say that even without anti-AIDS drugs, only a small percentage of babies become infected through breast milk.Sallie Permar is a professor of pediatrics (儿科) and immunology (免疫学) at Duke University Medical Center. She says the protein found in breast milk is called Tenascin-C. It works by blocking the virus from attaching to cells in the baby's body."This is a really exciting finding," Permar said. "It gives us a new target for developing drugs and other interventions to prevent HIV transmission from mother to child."The researchers tested the protein in the laboratory and found that it was effective in blocking the virus from infecting cells. They also showed that the protein is present in high levels in breast milk from women who are not infected with HIV, but its levels are reduced in women with the virus.(单选题 3分) What does Permar think of the discovery of Tenascin-C?A It can replace anti-retroviral drugs immediatelyB It has solved all problems of mother-to-child HIV transmissionC It is not useful for HIV preventionD It provides a new target for developing HIV prevention methods

To prevent infection, doctors give anti-retroviral drugs (抗逆转录病毒药) to both mothers and their babies, that has greatly reduced the number of infections. But experts say that even without anti-AIDS drugs, only a small percentage of babies become infected through breast milk. Sallie Permar is a professor of pediatrics (儿科) and immunology (免疫学) at Duke University Medical Center. She says the protein found in breast milk is called Tenascin-C. It works by blocking the virus from attaching to cells in the baby's body. "This is a really exciting finding," Permar said. "It gives us a new target for developing drugs and other interventions to prevent HIV transmission from mother to child." The researchers tested the protein in the laboratory and found that it was effective in blocking the virus from infecting cells. They also showed that the protein is present in high levels in breast milk from women who are not infected with HIV, but its levels are reduced in women with the virus. (单选题 3分) What does Permar think of the discovery of Tenascin-C? A It can replace anti-retroviral drugs immediately B It has solved all problems of mother-to-child HIV transmission C It is not useful for HIV prevention D It provides a new target for developing HIV prevention methods