For which pair will each compound produce a different observable outcome with alkaline I$_2$(aq)?
- A$\text{CH}_3\text{CH}_2\text{OH}$ and $\text{CH}_3\text{CHO}$
- B$\text{CH}_3\text{CHO}$ and $\text{CH}_3\text{COCH}_3$
- C$\text{CH}_3\text{COOH}$ and $\text{C}_2\text{H}_5\text{COC}_2\text{H}_5$
- D$\text{CH}_3\text{CH}_2\text{OH}$ and $\text{C}_2\text{H}_5\text{CHO}$