单选题 The primary purpose of the passage is to

• (A) expose the fragile ecological conditions which modern irrigation technologies must ameliorate
• (B) argue that new irrigation technologies would ultimately be less efficient than a reconfiguration of the North American diet
• (C) argue that efficient water-use is dependent upon a mixture of various modern methods
• (D) provide an overall view of possible methods for lessening the strain on sources of freshwater
• (E) describe the cycle by which aquifers are depleted and then replenished through technology