Final answer:
C. Capital and entrepreneurship. When an economist uses the word investment, they are typically referring to the factors of production known as capital and entrepreneurship.
Step-by-step explanation:
When an economist uses the word investment, they are typically referring to the factors of production known as capital and entrepreneurship. Capital refers to the tools, equipment, and goods that are used in the production of goods and services, while entrepreneurship refers to the individuals who organize and manage the factors of production. These two factors are essential for economic growth and development.