The correct answer is: "necessary capital".
In every economy, there are three types of economic agents (households, firms and public sector) that interact in the goods and services markets and in the factor markets.
Economic agents can either perform producer or consumer roles because, on one hand, they consume goods and services to satisfy their needs and, on the other hand, they need to obtain income to pay for the abovementioned products, therefore, they offer the factors of production they own (land, labor and capital) in the factor markets, in exchange for a retribution.
