12. The reactivity towards nucleophilic substitution of carboxylic acid derivatives in decreasing order (most to least). (A) acid anhydride ＞ acyl chloride ＞ ester ＞ amide (B) acid anhydride ＞ acyl chloride ＞ amide ＞ ester (C) acyl chloride ＞ acid anhydride ＞ amide ＞ ester (D) acid anhydride ＞ amide ＞ acyl chloride ＞ ester (E) acyl chloride ＞acid anhydride ＞ ester ＞ amide