Final answer:
In economics, investment refers to the purchase of new capital goods, commercial real estate, equipment, residential construction, and inventories for production and is a part of GDP. Financial investments like stocks and bonds do not fall under this definition.
Step-by-step explanation:
Definition of Investment in Economics-
When economists discuss the concept of investment, they refer to the act of purchasing new capital goods, such as commercial real estate, equipment, residential housing construction, and inventories produced by manufacturers. These assets must be new, meaning they contribute to the current production capacity. Investment in this sense is a component of calculating Gross Domestic Product (GDP), and it is distinct from the idea of financial investment that includes assets like stocks, bonds, or trading financial assets. For instance, business investment was substantial in recent years, with $3.6 trillion recorded by the Bureau of Economic Analysis in 2020.
Thus, when answering which of the provided options (stocks, bonds, real estate) would be included in the definition of investment as defined by economists, the correct response would be real estate—but specifically new capital in the commercial sector and new residential housing construction.