There are multiple original radio options in the Ford Explorer 3rd Gen (U152), which option is the original fitted system?

Enclosed Subwoofers/ Drivers Enclosed Subwoofers/ Drivers
Extra Slim Subwoofers Extra Slim Subwoofers
Spare Wheel Subwoofers Spare Wheel Subwoofers
Underseat Subwoofers Underseat Subwoofers