How does the polarity of the eluent and sample affect the Rf value in thin layer chromatography?
Never in my years in the lab have I seen a more polar eluent that causes a lower $R_\mathrm{f}$ value than a less polar eluent. It also does not make sense theoretically.

TLC 2 is obviously the one with the least polar eluent and compound $z$ is the least polar compound.

I fully disagree with half of MaxW’s proposed answer.