hi.....let the 4 nos. be-->> a(r^3),ar,a/r,a/(r^3)....Now after solving u'll obtain a=3,,,,,

See if u consider the 3rd term to be ar,then r=9......and if the 3rd term is considered to be a/r,then r=1/9.

So the ans. can either be considered true or false.So it is not wrong to consider r=9 as false bcoz no other info has been specified.