Which reaction is not a reduction?
CH3COOH→CH3CH2OH\text{CH}_3\text{COOH} \rightarrow \text{CH}_3\text{CH}_2\text{OH}CH3COOH→CH3CH2OH
CH3CH2CHO→CH3CH2CH2OH\text{CH}_3\text{CH}_2\text{CHO} \rightarrow \text{CH}_3\text{CH}_2\text{CH}_2\text{OH}CH3CH2CHO→CH3CH2CH2OH
CH3CH2Br→CH3CH2OH\text{CH}_3\text{CH}_2\text{Br} \rightarrow \text{CH}_3\text{CH}_2\text{OH}CH3CH2Br→CH3CH2OH
CH3CH=CH2→CH3CH2CH3\text{CH}_3\text{CH}=\text{CH}_2 \rightarrow \text{CH}_3\text{CH}_2\text{CH}_3CH3CH=CH2→CH3CH2CH3