Which of the following most logically completes the passage?
Laminated glass is much harder to break than the glass typically used in the windows of cars driven in Relnia. It is more difficult for thieves to break into cars with laminated glass windows than into cars with ordinary glass windows, and laminated glass windows are less likely to break in a collision. Nevertheless, considerations of security and safety do not unambiguously support a proposal to require that in Relnia all glass installed in cars be laminated glass, since_________.
【选项】some cars in Relnia already have laminated glass in their windows