Consider the sets defined by the real solutions of the inequalities
$$A = \{(x,y):x^2+y^4 \leq 1 \} \:\:\:\:\:\:\:\: B = \{ (x,y):x^4+y^6 \leq 1\}$$
Then
- $B \subseteq A$
- $A \subseteq B$
- Each of the sets $A – B, \: B – A$ and $A \cap B$ is non-empty
- none of the above