A system of internal control can be rendered ineffective by employee collusion. is infallible. invariably will have costs exceeding benefits. is premised on the concept of absolute assurance. The Sarbanes-Oxley Act applies to: a) all U.S. companies listed on U.S. exchanges. b) all companies that list stock on any stock exchange in any country. c) all European companies listed on European exchanges. d) both (a) and (c)