【单选题】

A、

A、It is a serious endemic disease in some areas of northwestChin

A、

B、It may lead to breast and prostate cancer.

C、It benefits 144,000 newborn babies and women of child-beating age in eight counties and cities in some areas ofChin

A、

D、It is regarded by scientists as the most common cause of preventable mental retardation and brain damage.