What is the number of peaks in the 1H^1\text{H}1H NMR spectrum of HOOCCH2CH2CHOHCH2CH2COOH\text{HOOCCH}_2\text{CH}_2\text{CHOHCH}_2\text{CH}_2\text{COOH}HOOCCH2CH2CHOHCH2CH2COOH?
3
4
5
6