Which of the following resources is classified as a free good in economic theory?
Naturally occurring wind blowing across an uninhabited mountain range
Open-source operating system software available for free download over the internet
Clean drinking water supplied free of charge from a municipal water fountain in a public park
Carbon-dioxide emission permits distributed at zero cost to heavy industries under a government cap-and-trade scheme
53 exam-style questions on OCR A Level Economics The economic problem. Each one has a worked solution and a mark scheme showing where the marks go.