If $A = \{(x, y): x^2 + y^2 ≤1, x, y ∈ R\}$ and $B=\{(x, y): x^2 + y^2≤4; x, y ∈ R\}$, then

$A - B = \phi$

The correct answer is Option (3) → $A - B = \phi$

Clearly, A is the set of all points lying inside or on the circle with centre at the origin and radius 1 and B is the set of all points lying inside or on the circle with centre at the origin and radius 2 units. Clearly, $A ⊂ B$. Therefore, $A - B = \phi$ and $B-A≠\phi$.