Which compound produces exactly two signals in its 1H^1\text{H}1H NMR spectrum, both of which are triplets?
ClCH2CH2COOCH3\text{ClCH}_2\text{CH}_2\text{COOCH}_3ClCH2CH2COOCH3
ClCH2CH2CN\text{ClCH}_2\text{CH}_2\text{CN}ClCH2CH2CN
CH3CH2CH2Cl\text{CH}_3\text{CH}_2\text{CH}_2\text{Cl}CH3CH2CH2Cl
ClCH2CH2CH2Cl\text{ClCH}_2\text{CH}_2\text{CH}_2\text{Cl}ClCH2CH2CH2Cl