Which isomer of C5H10O2\text{C}_5\text{H}_{10}\text{O}_2C5H10O2 produces the smallest number of peaks in its 13C^{13}\text{C}13C NMR spectrum?
Propyl acetate, CH3COOCH2CH2CH3\text{CH}_3\text{COOCH}_2\text{CH}_2\text{CH}_3CH3COOCH2CH2CH3
Isopropyl acetate, CH3COOCH(CH3)2\text{CH}_3\text{COOCH(CH}_3)_2CH3COOCH(CH3)2
2,2-dimethylpropanoic acid, (CH3)3CCOOH\text{(CH}_3)_3\text{CCOOH}(CH3)3CCOOH
Methyl 2-methylpropanoate, (CH3)2CHCOOCH3\text{(CH}_3)_2\text{CHCOOCH}_3(CH3)2CHCOOCH3
