Traverton's city council wants to minimize the city's average yearly expenditures on its traffi c signal lights and so is considering replacing the incandescent bulbs currently in use with arrays of light-emitting diodes (LEDs) as the incandescent bulbs burn out. Compared to incandescent bulbs, LED arrays consume signifi cantly less energy and cost no more to purchase. Moreover, the costs associated with the conversion of existing fi xtures so as to accept LED arrays would be minimal.

Which of the following would it be most useful to know in determining whether switching to LED arrays would be likely to help minimize Traverton's yearly maintenance costs?

• AWhether the expected service life of LED arrays is at least as long as that of the currently used incandescent bulbs  
• BWhether any cities have switched from incandescent lights in their traffi c signals to lighting elements other than LED arrays  
• CWhether the company from which Traverton currently buys incandescent bulbs for traffi c signals also sells LED arrays  
• DWhether Traverton's city council plans to increase the number of traffic signal lights in Traverton  
• EWhether the crews that currently replace incandescent bulbs in Traverton's traffi c signals know how to convert the existing fixtures so as to accept LED arrays