If the airspace around centrally located airports were restricted to commercial airliners and only those private planes equipped with radar, most of the private-plane traffic would be forced to sue outlying airfields. Such a reduction in the amount of private-plane traffic would reduce the risk of midair collision around the centrally located airports.

The conclusion drawn in the first sentence depends on which of the following assumptions?

• AOutlying airfields would be as convenient as centrally located airports for most pilots of private planes.  
• BMost outlying airfields are not equipped to handle commercial-airline traffic.  
• CMost private planes that use centrally located airports are not equipped with radar.  
• DCommercial airliners are at greater risk of becoming involved in midair collisions than are private planes.  
• EA reduction in the risk of midair collision would eventually lead to increases in commercial airline traffic.