Problem $3$: Sets and Counterexamples

Show that for arbitrary sets $A,B,$ and $C,$ taken from the universe $\{1,2,3,4\},$ the following

claims are not always true by using a simple counter example for each:

$($a$)(AB)sup(ABC)$

$($b$)$ if Csube$(AB),$ then $(AB)subeC$

$($c$)$ if $(AB)subeC,$ then Csube$(AB)$

show work