The three compounds below are given: - copper(II) nitrate, $\text{Cu(NO}_3)_2$ - zinc sulfate, $\text{ZnSO}_4$ - sodium thiosulfate, $\text{Na}_2\text{S}_2\text{O}_3$ Which row shows the element that makes up the largest percentage by mass in each compound? Relative formula masses, $M_r$: $\text{Cu(NO}_3)_2 = 188$; $\text{ZnSO}_4 = 161$; $\text{Na}_2\text{S}_2\text{O}_3 = 158$
- Acopper; oxygen; oxygen
- Bcopper; oxygen; sulfur
- Coxygen; zinc; sodium
- Doxygen; zinc; sulfur