Net social benefit of the dam project

Steps:

• Identify social benefits as total gains to society from the dam, such as flood control and power generation.
• Identify social costs as total losses to society, including environmental damage and displacement.
• Subtract social costs from social benefits to find the difference (net social benefit).
• Use given project data showing benefits of $300 million and costs of$100 million.

Why D is correct:

• The difference equals $200 million, matching the net social benefit formula: Benefits - Costs = Net Benefit.

Why the others are wrong:

• A miscalculates by ignoring full benefits, yielding only partial gains.
• B underestimates the scale, perhaps confusing private vs. social values.
• C overlooks major cost components like ecological impacts.

Final answer: D