Normal Phase TLC using ethyl acetate as eluent
TLC is only about polarity. 
Since all three compounds share the benzoic acid functionality, we only have to consider the rest. 
Then we have three compounds: $\ce{R-OCOCH3}$, $\ce{R-OH}$ and $\ce{R-H}$.

In general the polarity is:

alkane &lt; ester &lt; alcohol


That is what we have here also: 3 &lt; 1 &lt; 2.

The one with the lowest polarity will have the highest R$_f$. 
To show that it works, I have run them on a silica TLC plate with AcOEt:



AcSA: acetylsalicylic acid; SA: salicylic acid; BA: benzoic acid.