The town of Isle is on a small island connected to Big City by a single bridge. Most of the residents of Isle work in Big City. As a result, the bridge becomes very congested for two hours each day at the typical morning and evening commute times. Which of the following policies considered by the mayor of Isle would likely be most efficient in alleviating the congestion? a. A fixed toll for the bridge payable by every vehicle crossing the bridge at all days and times. b. A press conference in which the mayor requests that people try to cross the bridge earlier or later than the typical commute times. c. Any vehicle crossing the bridge at any time must have a sticker paid for with a one-time fee of $25.