A brass rod $($Y $=1$ x $10^11$ Pa$)$ and a steel rod $($Y $=2$ x $10^11$ Pa$)$ of the same dimensions are subjected to identical squeezing forces on their ends.

$($a$)$ Which experiences the greater compressive stress, the brass rod or the steel rod?

$($b$)$ Which undergoes the greater compressive strain?

$($c$)$ Which undergoes the greatest change in length?