What are the mass percentages of nitrogen in ammonium nitrate, NH$_4$NO$_3$, and in calcium nitrate, Ca(NO$_3$)$_2$?
- A18% in NH$_4$NO$_3$; 14% in Ca(NO$_3$)$_2$
- B18% in NH$_4$NO$_3$; 17% in Ca(NO$_3$)$_2$
- C35% in NH$_4$NO$_3$; 9% in Ca(NO$_3$)$_2$
- D35% in NH$_4$NO$_3$; 17% in Ca(NO$_3$)$_2$