کدام یک افرازی برای مجموعهٔ $\left\{ \varnothing ,\left\{ \varnothing ,\left\{ \varnothing  \right\} \right\},\left\{ \varnothing  \right\} \right\}$ است؟
1 $\left\{ \varnothing  \right\},\left\{ \varnothing ,\left\{ \varnothing ,\left\{ \varnothing  \right\} \right\} \right\}$
2 $\left\{ \left\{ \varnothing  \right\} \right\},\left\{ \left\{ \varnothing ,\left\{ \varnothing ,\left\{ \varnothing  \right\} \right\} \right\} \right\}$
3 $\left\{ \left\{ \varnothing  \right\} \right\},\left\{ \varnothing ,\left\{ \varnothing ,\left\{ \varnothing  \right\} \right\} \right\}$
4 $\left\{ \left\{ \, \right\} \right\},\left\{ \varnothing ,\left\{ \varnothing ,\left\{ \varnothing  \right\} \right\} \right\}$