❓ 質問 According to the passage, why is the valuation of ecosystem services considered challenging?
- A. A. Because provisioning services are more important than regulating services.
- B. B. Because services are often interdependent and cultural values are difficult to quantify monetarily.
- C. C. Because contingent valuation is the only method available, yet it is unreliable.
- D. D. Because supporting services do not produce any benefits to humans.