а) CH3-CHCH3CH3CH3-CH2-CHCH3CH3CH3-CH2-CHCH2CH3CH2CH3CH2CH3-CH3
б) CH3-CHCH3CH3CH3-CH2-CHCH3CH3CH3-CHCH2CH3CH2CH3CH2CH3-CH3
в) CH3-CH2-CHCH3CH3CH3-CH2-CHCH3CH3CH3-CHCH3CH3CH3-CH2-CH3
а) CH3-CHCH3CH3CH3-CH2-CHCH3CH3CH3-CH2-CHCH2CH3CH2CH3CH2CH3-CH3
б) CH3-CHCH3CH3CH3-CH2-CHCH3CH3CH3-CHCH2CH3CH2CH3CH2CH3-CH3
в) CH3-CH2-CHCH3CH3CH3-CH2-CHCH3CH3CH3-CHCH3CH3CH3-CH2-CH3