Answer:
b) natural resources
Step-by-step explanation:
Natural resources refer to valuable materials found beneath, above, and on the earth's surface. They are naturally occurring, meaning no human effort is required in producing them. Natural resources make a good source of wealth. Examples of natural resources are land, mineral, oils and gas, forests, water, sunlight, wind, and many others.
Anyone with access to natural resources can invest to make them marketable products. Extraction of oil and refining is an example of investing in natural resources. Processing of trees to wood, use of solar to generate power are other examples.