The figure below shows a section of the iron$-$carbon equilibrium diagram. Consider $2\mathrm{.}5kg$ of steel containing $0\mathrm{.}65wt\%C,$ heated up to the austenite region and then cooled immediately below $727C.$

$($a$)$ Name the primary $($proeutectoid$)$ phase.

$($b$)$ How many kilograms each of total ferrite and total cementite form?

$($c$)$ How many kilograms each of pearlite and the proeutectoid phase form?

$($d$)$ What is the mass of carbon in the pearlite?

$($e$)$ What is the mass of the ferrite in the pearlite?

Figure $2$