The reaction is:

When molecular hydrogen ( H2) and oxygen ( O2 ) is combined they form either water or hydrogen peroxide.
We have that mass of hydrogen is 16 g and mass of oxygen is 16 g. But O2 is the limiting reactant. Let`s see how much grams of hydrogen can be used for this reaction:
16 g O2 x (1 mol O2)/ (32 g O2) x ( 2 mol H2)/(1 mol O2)x (2 g H2) / (1 mol H2) = 2 g H2
Finally: 16 g + 2 g = 18 g.
Answer:
C. 18 grams of water.