California's State Board of Equalization imposed a higher tax on "alcopops," flavored beers containing more than $0.5 \%$ alcohol-based flavorings, such as vanilla extract. Such beers are taxed as distilled spirits at $\$ 3.30$ a gallon rather than as beer at 20 \& a gallon. In response, manufacturers reformulated their beverages so as to avoid the tax. By early 2009 instead of collecting a predicted $\$ 38$ million a year in new taxes, the state collected only about $\$ 9,000$ (Guy L. Smith,“On Regulation of 'Alcopops," " San Francisco Chronicle, April 10,2009 ). Use an isocost-isoquant diagram to explain the firms' response.