Which of these is the best choice for measurement?
None of these
None of the options are best choice for measurement .Footstep , handspan or oranges both differ in terms of size . If this would be used as SI unit there would be a lot of confusion because if something is large for someone then it would be small for the other.So, meter is used to remove this confusion. So, from this we can conclude that neither footsteps nor handspans cannot be used as a standard unit of measurement .