Which compound is a 3-aminocarboxylic acid?
CH3CH(NH2)COOH\text{CH}_3\text{CH}(\text{NH}_2)\text{COOH}CH3CH(NH2)COOH
H2NCH2CH2COOH\text{H}_2\text{NCH}_2\text{CH}_2\text{COOH}H2NCH2CH2COOH
CH3CH2CH(NH2)COOH\text{CH}_3\text{CH}_2\text{CH}(\text{NH}_2)\text{COOH}CH3CH2CH(NH2)COOH
H2NCH2COOH\text{H}_2\text{NCH}_2\text{COOH}H2NCH2COOH