What conversion factor will help solve the problem? 2HgO → 2Hg + O2

How many moles of mercury (II) oxide are needed to make 125 grams of O2

125 g O2 x ___1 mol__O2 x = mols HgO

32.00 g O2

a
2 mol Hg

1 mol O2

b
216.6 g HgO

1 mol HgO

c
1 mol O2

2 mol HgO

d
2 mol HgO

1 mol O2