Which is an example of a capital resource?

metal tools
low-cost labor
an abundance of coal
a clean water supply

A capital resource refers to goods that are used in the production of other goods or services. These are man-made tools, equipment, machinery, and buildings used in the production process. Among the options provided, "metal tools" is an example of a capital resource, as they are manufactured objects that can be used in the production of other goods or services.