Answer: A) Designated bike lanes have reduced traffic-related accidents by 43 percent in other cities.
Explanation: In the given scenario we can see that a city planner thinks that allow bike lanes in downtown is worth the cost because it will help drivers and cyclists to avoid accidents. From the given options, the fact that best supports the city planner's opinion, is the corresponding to option A: Designated bike lanes have reduced traffic-related accidents by 43 percent in other cities, because it provides statistics (reliable and objective evidence) about the reduction of traffic-related accidents.
