The problem statement doesn't specify if the compounds to be eluted are polar or non-polar. So this seems to leave a door open.
Question 1 - Could compounds be either relatively polar or relatively non-polar?
Question 2 - If an absolutely non-polar solvent like hexane were used, and some other more polar solvent, wouldn't a reversal of the order of the elution of the compounds happen?
Question 3 - Have I in fact, like a blind squirrel, finally found the nut?
The problem specifies that "normal phase TLC" is being used so the stationary phase is polar.
The problem only states that the elutants have different polarity and not that any is actually non-polar like hexane.
With Question 3 I was trying to be funny and ask if my two answers to the original question are right.