Let $S _ { 1 } , S _ { 2 }$ and $S _ { 3 }$ be three sets defined as
$S _ { 1 } = \{ z \in \mathbb { C } : | z - 1 | \leq \sqrt { 2 } \}$,
$S _ { 2 } = \{ z \in \mathbb { C } : \operatorname { Re } ( ( 1 - i ) z ) \geq 1 \}$ and
$S _ { 3 } = \{ z \in \mathbb { C } : \operatorname { Im } ( z ) \leq 1 \}$.
Then, the set $S _ { 1 } \cap S _ { 2 } \cap S _ { 3 }$\\
(1) is a singleton\\
(2) has exactly two elements\\
(3) has infinitely many elements\\
(4) has exactly three elements