I’m stuck on this problem.. please help!

Answer:
1.72 mol
Explanation:
Given data:
Mass of NaCl = 200 g
Moles of Na₂O formed = ?
Solution:
Chemical equation:
MgO + 2NaCl → Na₂O + MgCl₂
Number of moles of NaCl:
Number of moles = mass/ molar mass
Number of moles = 200 g/ 58.44 g/mol
Number of moles = 3.422 mol
Now we will compare the moles of NaCl with Na₂O.
NaCl : Na₂O
2 : 1
3.422 : 1/2×3.422 = 1.71 mole
Approximately equal to 1.72 so option A is correct.