Which type of trademark protects the appearance of a product as a whole?

The correct answer is trade dress because it specifically refers to the overall appearance or design of a product, which includes elements such as shape, color, texture, and graphics. Trade dress is a crucial aspect of trademark law that seeks to protect the distinctive visual appearance of a product or its packaging, ensuring that consumers can identify the source of the product based on its look. This type of trademark helps prevent consumer confusion and protects the brand's identity in the marketplace.

In other contexts, service marks are used to identify and distinguish the services of one provider from another, rather than the appearance of a physical product. Collective marks are used by members of a collective group to indicate membership or association, not to protect a product's appearance. Color trademarks protect a specific color used in connection with a product or service, but they do not encompass the overall visual appearance as trade dress does. Each of these other types of trademarks serves a different protective purpose, which is why trade dress is the definitive choice for protecting the overall appearance of a product.