Which of the following statements is false according to econometrics statistics?
a) A five-firm concentration ratio assesses firms’ sizes with reference to the number of employees, and shows the percentage of total employment in an industry accounted for by the five firms with the most employees.
b) The firms in an industry with a high concentration ratio may, nevertheless, find themselves in a highly competitive environment.
c) Economic profits in a contestable market attract new entrants.
d) In deciding whether to produce inputs or buy them, firms take account of transactions costs.