کدام گزینه افرازی از مجموعهی $A=\left\{ 1,2,3,4,5,6,7,8,9 \right\}$ است؟
1 )
$\left\{ 7,8 \right\}\,,\,\left\{ 3,4,9 \right\}\,,\,\left\{ 1,2,6 \right\}$
2 )
$\left\{ 6,8,9 \right\}\,,\,\left\{ 1,2,3,4 \right\}\,,\,\left\{ 3,5,7 \right\}$
$\left\{ 6,7,8,9 \right\}\,,\,\left\{ 3,4,5 \right\}\,,\,\left\{ 1,2 \right\}$
4 )
$\left\{ 6,7,8,9 \right\}\,,\,\left\{ 1,2,3,4,5 \right\}\,,\left\{ {} \right\}$