An industry consists of three firms with sales of $200,000, $710,000, and $325,000. a. Calculate the Herfindahl-Hirschman index (HHI). Instruction: Round to the nearest integer. b. Calculate the four-firm concentration ratio (C4). c. Based on the FTC and DOJ Horizontal Merger Guidelines described in the text, is the Department of Justice likely to attempt to block a horizontal merger between two firms with sales of $200,000 and $325,000?