Which of the following is a notable exception to the three-tier system in many states?

A brewpub that serves its own beer is a notable exception to the three-tier system in many states because it represents a business model where the brewery and the retail outlet coexist. Under the typical three-tier system, which separates producers (breweries), wholesalers (distributors), and retailers (bars and stores), a brewpub operates uniquely by allowing the brewery to sell its beer directly to consumers on-site. This setup not only promotes direct consumer access to fresh beer but also encourages local craft brewing by providing a venue where these operations can thrive. Additionally, brewpubs often have advantages in flexibility when it comes to licensing and local regulations, enabling them to operate in ways that traditional breweries might not be allowed to. This distinguishes them from larger-scale breweries, distributors, and wholesalers that must adhere strictly to the segmented nature of the three-tier regulatory framework.