Which of the options $($A$,$ B$,$ C and D$)$ are true. Show your work to

prove it$.$

A$.$ heat flow through A and $E$ slabs are same.

B$.$ heat flow through slab $E$ is minimum.

C$.$ temperature difference across slab $E$ is minimum.

D$.$ heat flow through $C=$ heat flow through $B+$ heat flow through $D.$