Reaction of para-Chloroaniline with acetic anhydride in pyridine gave a crude mixture of 94% of para-chloroacetanilide and 6% unreacted amine. From the following, the best treatment suitable for purification of para-chloroacetanilide is

A

treating the reaction mixture with methyl iodide

B

washing an ether solution of the crude product with concentrated brine (aq. NaCl)

C

washing an ether solution of the crude product with 5% cold aqueous sulfuric acid

D

washing an ether solution of the crude product with 5% aqueous sodium carbonate