What is the concept of "trademark infringement"?

The concept of trademark infringement refers specifically to the unauthorized use of a trademark on goods or services. This means that when someone uses a trademark that is identical or confusingly similar to a registered trademark without permission from the owner, it can lead to consumer confusion regarding the source of the goods or services. Trademark infringement is primarily concerned with the protection of the interests of both the trademark owner and consumers, as it helps to ensure that consumers can identify the source of goods and services and avoid being misled.

In contrast, obtaining trademark registration involves a formal process where a company or individual files an application with the relevant trademark office to establish legal rights to a trademark. Legal requirements for trademark renewal relate to the ongoing maintenance of trademark rights, ensuring that the trademark remains protected over time. Lastly, a trademark licensing agreement involves a legal relationship where the trademark owner permits another party to use the trademark under specified conditions, which is an entirely different concept from infringement. Thus, the focus on unauthorized use in the context of trademark infringement solidifies the rationale that option A is the correct answer.