Which of the following describes a trademark?

A trademark is defined as a distinctive mark or emblem used to identify goods and differentiate them from those of other entities. This means that it serves as an identifier of the source of the goods or services, indicating to consumers the origin of the product. Trademarks can take various forms, including logos, symbols, words, or a combination of these elements, and they are protected under intellectual property law to prevent unauthorized use by competitors.

The other options do not accurately capture the essence of what a trademark is. A legal agreement between countries pertains to treaties or trade agreements and does not pertain to trademarks. Details about legal procedures relate to the processes involved in judicial or administrative function, rather than to the concept of trademarks. An unlawful act regarding personal property typically refers to theft or vandalism, which is unrelated to the identification and protection of goods through trademarks. Hence, the description that identifies a trademark as a distinctive mark or emblem is the only correct characterization among the provided options.