In economics, investment always refers to

A) the act of buying stocks or bonds.
B) the creation of capital.
C) increasing the quantity of labor.
D) an increase in per capita output.

Investment

Allocating resources, usually money, with the expectation of generating an income or profit.

Capital

Assets or money owned by an individual or organization, or funds available for specific purposes like establishing a company or investment.

Stocks

Shares of ownership in a corporation, representing a claim on the company's assets and earnings.