TOEFL Reading: ETS-TOEFL阅读机经 - 6EL7M7W4BA051IWEL$

In paragraph 6, the author refers to Tokyo, Japan, in order to A. explain why Japan is not likely to experience problems with soil erosion in the future B. provide evidence of the importance of maintaining cropland close to big cities C. point to an approach for reducing urban spread into croplands that has had positive results D. argue for the use of Japanese techniques to prevent erosion in the United States