Suppose an excise tax of $1 is imposed on every case of beer sold and sellers are responsible for paying this tax. how would the imposition of the tax be illustrated in a graph? a. the supply curve for cases of beer would shift down by $1. b. the supply curve for cases of beer shifts up by $1. c. the supply curve for cases of beer would shift up by less than $1. d. the supply curve for cases of beer would shift up by more than $1.