A Mixture of the Three Amino Acids Shown Below Was

A mixture of the three amino acids shown below was buffered to pH 7.0 and placed in the center of an electric field with the cathode to the left and the anode to the right. From left to right, what would be the positional order of the amino acids after sufficient time to allow migration?

A) A, B, C
B) B, C, A
C) B, A, C
D) C, B, A
E) C, A, B