❓ 题目 According to the passage, what is a major reason why supporting services are often undervalued?
- A. A) They are not included in the four categories of ecosystem services.
- B. B) They provide benefits that are indirect and not immediately visible in economic terms.
- C. C) They are primarily cultural and therefore difficult to quantify.
- D. D) They have been fully replaced by technological solutions in modern agriculture.