Final answer:
The Chamber of Commerce is the business association that represents a wide range of businesses from small to large employers, and it works to influence public policy through various means such as lobbying.
Step-by-step explanation:
The business association that represents three million businesses ranging from small mom and pop stores to large employers is the Chamber of Commerce. Trade associations like the Chamber of Commerce work to influence public policy in ways that are favorable to their members' interests. These trade associations, such as the Aerospace Industries Association, Alliance of Automobile Manufacturers, and others seek to impact legislation and regulations through lobbying and political action committees (PACs). Additionally, they provide support for their members by negotiating better working conditions and benefits, and often have a presence in Washington, DC to advocate effectively for their industry. For businesses, this collective effort can lead to benefits such as tax breaks or eased regulations that help all members.