The Costa Rican gimble industry consists of 14 firms whose annual sales are as shown in the table below: Firm Sales (in millions) A 6 B 7 C 8 D 9 E 13 F 14 Next eight firms (total) 31 a. What is the (four-) firm concentration ratio for this industry? Four firm concentration: % b. In what type of market does the gimble industry operate? Market type: (Click to select)