Which one of the following undergoes decarboxylation most readily?
A. `CH_(3)-overset(O)overset(||)C-COOH`
B. `CH_(3)overset(O)overset(||)C"C"H_(2)CH_(2)COOH`
C. `CH_(3)-overset(O)overset(||)C"C"H_(2)COOH`
D. `CH_(3)overset(O)overset(||)C(CH_(2))_(3)COOH`