The skeletal formulae for arginine and lysine are shown. Which row is correct?
- Aarginine, $\text{C}_3\text{H}_7\text{N}_2\text{O}$, $M_r = 174$
- Barginine, $\text{C}_3\text{H}_8\text{N}_2\text{O}$, $M_r = 176$
- Clysine, $\text{C}_3\text{H}_7\text{NO}$, $M_r = 144$
- Dlysine, $\text{C}_3\text{H}_8\text{NO}$, $M_r = 146$