Hi, can you please show that this violates the weak axiom of revealed preference

Let X = {x, y, z}. Consider the choice structure (B, C() ) with B = {{x, y), (y, z), {x, z), {x, y, z} } and C((x, y)) = (x], C((y, z)) = {y), and C({x, z]) = {z}. Show that (B, C(.)) violates the Weak Axiom of Revealed Preference