Moles of oxygen atoms per gram depend on oxygen atoms per formula unit divided by formula mass.

Steps:

• Calculate formula masses: Al₂O₃=102, CuO=79.5, H₂SO₄=98, HNO₃=63.
• For 1g, moles of compound = 1 / formula mass.
• Moles of O atoms = moles of compound × number of O atoms per formula (3 for A, 1 for B, 4 for C, 3 for D).
• Compare: A=3/102≈0.029, B=1/79.5≈0.013, C=4/98≈0.041, D=3/63≈0.048 (highest).

Why D is correct:

• HNO₃ has the highest ratio of oxygen atoms to formula mass (3/63), maximizing moles of O per gram.

Why the others are wrong:

• A: Al₂O₃'s high mass (102) yields fewer moles of O despite 3 atoms.
• B: CuO has only 1 O atom and higher mass (79.5), lowest O moles.
• C: H₂SO₄'s 4 O atoms offset by mass (98), less than D's ratio.

Final answer: D