Which trademark refers to actual goods or services and cannot be trademarked?

The answer is correct because a generic trademark refers to a term that is commonly used to identify a general category of goods or services rather than a specific source. These marks do not distinguish one brand from another and are considered part of the public domain, meaning they cannot be trademarked. For example, terms like "computer" for computing devices or "bicycle" for cycles cannot be owned by any one company, as they are widely used to refer to all products within that category.

In contrast, a certification mark, fanciful mark, and arbitrary mark are all types of trademarks that can be registered because they serve to identify the source of goods or services and indicate their quality or distinctiveness. Certification marks signify that the goods or services meet certain standards, fanciful marks are inventive and have no prior meaning (like "Xerox" for copiers), and arbitrary marks use common words in a way unrelated to their ordinary meanings (like "Apple" for computers). Since generic trademarks do not fulfill the purpose of identifying a source, they cannot receive protection under trademark law.