Which sample contains the largest amount, in mol, of oxygen atoms?

A.     0.20 mol ${{\text{P}}_{\text{2}}}{{\text{O}}_{\text{5}}}$

B.     0.30 mol ${{\text{O}}_{\text{3}}}$

C.     0.40 mol ${\text{C}}{{\text{H}}_{\text{3}}}{\text{COOH}}$

D.     0.80 mol ${{\text{H}}_{\text{2}}}{\text{O}}$

A