Explanation:

- Capital Loss: This term refers to a decrease in the value of a capital asset when it sells for less than its original purchase price.

- Capital Gain: This occurs when a capital asset, such as stocks or property, is sold for more than its original purchase price, resulting in a profit.

- Capital Formation: This is the process of increasing the stock of real capital in an economy. It involves the accumulation of physical assets, such as machinery, buildings, and infrastructure, which contribute to economic growth. Therefore, capital formation is known as the increase in the stock of capital.

- None of These: This option applies when none of the provided answers are correct.