Which volumes of gases at standard temperature and pressure have the same mass as ${\text{100 c}}{{\text{m}}^{\text{3}}}$ of ${{\text{O}}_{\text{2}}}$?

I.     ${\text{50 c}}{{\text{m}}^{\text{3}}}$ of ${\text{S}}{{\text{O}}_{\text{2}}}$

II.     ${\text{100 c}}{{\text{m}}^{\text{3}}}$ of ${\text{C}}{{\text{H}}_{\text{4}}}$

III.     ${\text{100 c}}{{\text{m}}^{\text{3}}}$ of ${\text{Si}}{{\text{H}}_{\text{4}}}$

A.     I and II only

B.     I and III only

C.     II and III only

D.     I, II and III

B