In an Edgeworth box economy, do the following:

$($a$)$ Sketch a situation where preferences are neither convex nor strictly monotonic and there is no

Walrasian equilibrium.

$($b$)$ Sketch a situation where preferences are neither convex nor strictly monotonic yet a Walrasian

equilibrium exists nonetheless.

$($c$)$ Repeat parts $($a$)$ and $($b$),$ but this time assume preferences are not continuous.