Which of the following has carboxylic acid derivatives listed in order of decreasing reactivity in nucleophilic acyl substitution reactions? a. (CH_3CO)_2O > CH_3COCl > CH_3COOH_3 > CH_3CONH_2 b. CH_3COCl > (CH_3CO)_2O > CH_3COOCH_3 > CH_3CONH_2 c. CH_3CONH_2 > CH_3COOCH_3 > (CH_3CO)_2O > CH_3COCl d. CH_3COCl > (CH_3CO)_2O > CH_3CONH_2 > CH_3COOH_3