TOEFL Reading: ETS-TOEFL阅读机经 - V73D53K1SJ6F7BH3L$

Which of the following best describes how paragraph 6 relates to paragraph 5? A. Paragraph 6 describes how the solution to a problem identified in paragraph 5 created unexpected benefits. B. Paragraph 6 compares two possible solutions to a problem described in paragraph 5. C. Paragraph 6 explains how the attempt to solve a problem introduced in paragraph 5 led to more difficult problems. D. Paragraph 6 explains one way in which a difficulty described in paragraph 5 was resolved.