A highway agency is considering two alternative energy attenuation systems, described below, to lessen the severity of crashes into bridge columns and other fixed object hazards. System A has low initial cost but must be repaired extensively after each “hit”. System B has high initial cost but needs little maintenance. It is expected that such a device will be hit once every two years. On the basis of present worth concept, which system is preferred? Use an annual interest rate of 7 percent.