47. Why is China mentioned in the first paragraph?
(A) Significant changes to Chinese life styles have promoted their longevity.
(B) After 1990’s Chinese people have begun a new movement of practicing Tai Chi.
(C) The death rate in China since 1990’s surpasses the average death rate of the world.
(D) The medical data in China illustrate the linkage between the increase of mortality and the decrease of exercise.