Refer to Exhibit 20-6. Suppose the three equilibrium quantities are 700, 800, and 900, and the two other equilibrium prices are $2.20 and $2.75. What is the change in total revenue when a per-unit tax shifts S1 to S2, given that D2 is the relevant demand curve? Group of answer choices $260 -$260 $900 $700 -$200