❓ 题目 According to the passage, what is a major challenge for payment for ecosystem services (PES) schemes?
- A. A) They often fail to account for provisioning services like food and water.
- B. B) They require clear property rights and effective monitoring to prevent issues like leakage.
- C. C) They are only applicable in developed countries with strong legal systems.
- D. D) They prioritize cultural services over regulating services, causing imbalances.