The Gleaming Company has just developed a new dishwashing liquid and is preparing for a national tel- evision promotional campaign. The firm has decided to schedule a series of 1-minute commercials during the peak homemaker audience viewing hours of 1 to 5 p.m. To reach the widest possible audience, Gleam- ing wants to schedule one commercial on each of four networks and to have one commercial appear during each of the four 1-hour time blocks. The exposure rat- ings for each hour, which represent the number of viewers per $1,000 spent, are presented in the follow- ing table. Which network should be scheduled each hour to provide the maximum audience exposure?