In the US, this practice is prohibited by the Robinson-Patman Act when it causes “primary line” competitive injury across state borders. Marcel Boiteux (“bwah-TUH”) built upon Frank Ramsey’s finding that this practice may maximize social welfare. The two-part tariff (-5[1])is an example of this practice in which a product has both lump-sum and (10[1])per-unit components. (-5[1])The third-degree version of this practice relies on (10[2])an exogenous signal to segment a market. When this practice is performed perfectly, deadweight loss and consumer surplus are eliminated. (-5[1])This practice (-5[1])usually disadvantages consumers (0[1])with lower elasticities of demand. For 10 points, name this practice exemplified by senior discounts, (10[1])in which a firm charges different amounts to different customers. (10[1])■END■ (10[1]0[2])