题目选项分析

The hepatitis B virus is common in China relative to other countries in the region. The disease can easily be prevented through vaccination, regulation of barbershop and manicure practices, and health education. Yet, the incidence of this disease continues to rise in China, while it remains stable or is falling in China's neighboring countries.

Which of the following, if true, would best explain the situation described above?

【选项】Twenty years ago, a complete and accurate study by an international health agency revealed that the incidence of hepatitis B was much higher in China than in neighboring countries.