how do you solve this ?

1mol of Ba contains
[tex]\\ \sf\longmapsto 6.023\times 10^{23}atoms[/tex]
No of moles in 17atoms
[tex]\\ \sf\longmapsto \dfrac{No\:of\:atoms}{Avagadro\:no}[/tex]
[tex]\\ \sf\longmapsto \dfrac{17}{6.023\times 10^{23}}[/tex]
[tex]\\ \sf\longmapsto 2.82298\times 10^{-23}mol[/tex]
Option 2