Correct Option: B. a certain percentage on the value of a commodity Explanation of the Correct Answer An ad valorem tax is a type of tax based on the value of a transaction or property. The term "ad valorem" is Latin for "according to value." This means that the tax is calculated as a percentage of the value of the good or service being taxed. For example, if a product is sold for $100 and the ad valorem tax rate is 10%, the tax would be $10 (10% of $100). This type of tax is commonly applied to goods and services, such as sales tax or property tax, where the amount of tax owed increases with the value of the item. Why the Other Options Are Incorrect

• Option A: A total amount of an income tax
• This option is incorrect because an income tax is typically a fixed amount or a percentage of an individual's earnings, not based on the value of a commodity. Income tax is assessed on income earned, not on the value of goods or services.
• Option C: A certain percentage tax on the volume of commodity
• This option is misleading because it suggests that the tax is based on the quantity or volume of the commodity rather than its value. A tax based on volume would be a specific tax (like a per-gallon tax on gasoline), not an ad valorem tax. Ad valorem taxes are specifically tied to the value, not the quantity.
• Option D: A tax on capital gain
• This option is incorrect because a capital gains tax is levied on the profit made from the sale of an asset, such as stocks or real estate, rather than on the value of a commodity at the point of sale. While capital gains taxes can be a percentage of the profit, they do not fit the definition of an ad valorem tax, which is applied to the value of goods and services.

Summary of Key Concepts

1. Definition: An ad valorem tax is a tax based on the value of a good or service, calculated as a percentage of that value.
2. Common Examples: Sales tax and property tax are typical examples of ad valorem taxes.
3. Calculation: To calculate the tax, multiply the value of the commodity by the tax rate (e.g., Tax = Value × Tax Rate).
4. Distinction: It is important to distinguish ad valorem taxes from specific taxes, which are based on quantity or volume.

Revision Summary

• An ad valorem tax is based on the value of a commodity, not a fixed amount or quantity.
• It is calculated as a percentage of the value of the good or service.
• Common examples include sales tax and property tax.
• Understanding the difference between ad valorem and specific taxes is crucial for economic concepts.