Answer
C. CH3CH(CH3)CH2COOH 3-methylbutanoic acid.
Step-by-step explanation
A. CH3CHClCH2COOH
The name of the compound should be 3-chlorobutanoic acid and not 2-chlorobutanoic acid.
B. CH3CH2CHBrCHClCH3
The name of the compound is 3-bromo-2-chloropentane and not 2-chloro-3-bromopentane. This is because you must count from the side in which the functional group is assigned the least number and the naming should also be in alphabetical order.
C. CH3CH(CH3)CH2COOH
The name of the compound is 3-methylbutanoic acid. Hence, the compound is named correctly.
D. CH3C(CH3)2CH2COOH
The correct name of the compound is 3, 3-dimethylbutanoic acid.