Which compound is the only substance that is a gas at room temperature and pressure?
- A$\text{CH}_3\text{CH}_2\text{CH}_2\text{NH}_2$, $M_r = 59.0$
- B$\text{CH}_3\text{CH}_2\text{CH}_2\text{OH}$, $M_r = 60.0$
- C$\text{CH}_2\text{OHCH}_2\text{OH}$, $M_r = 62.0$
- D$\text{CH}_3\text{CH}_2\text{Cl}$, $M_r = 64.5$