Which one of the following is NOT a type of interest?

The choice indicating "Net investment income tax" is correct because it refers to a tax, not a type of interest. Interest represents the cost of borrowing money or the income generated from lending it, typically expressed as a percentage of the principal amount over time. Simple interest is calculated solely on the principal amount, while compound interest involves interest on both the initial principal and the accumulated interest from prior periods, leading to potentially greater returns over time.

In contrast, a tax does not fall under the category of interest. Net investment income tax is an additional tax applied to certain types of investment income, such as capital gains and dividends, and is not a financial interest earned or charged.

Tax loss carryforward is also not a type of interest; instead, it is an accounting provision that allows taxpayers to use a current year's tax loss to offset taxable income in future years. This further emphasizes that the selected answer pertains to a tax concept rather than a type of interest, making it the correct choice.