1) The method of guidance is irrelevant to the argument about freewheel versus fixed linear systems 2) The passage compares the speed and system models of airplanes and high -speed trains. The argument does not incorporate buses and cars, which are included only to give examples of free -wheel system, and so this statement is irrelevant. 3) This statement properly identifies the weakness in the argument: Airplanes are not truly a free -wheel system because they are restricted to travelling between airports. Additionally airports tend to be less conveniently located than train terminals, which have further potential to weaken the argument in favour of airplanes. 4) The inability of high-speed trains to use some convenient train stations strengthens, rather than weakens, the argument in favour of airplanes. 5) Consumer preference for air travel over ground travel on long trips strengthens, rather than weakens, the argument in favour of airplanes.