The PK₁,pK₂,and PK_R of the Amino Acid Lysine Are 2

The pK₁,pK₂,and pK_R of the amino acid lysine are 2.2,9.1,and 10.5,respectively.The pK₁,pK₂,and pK_R of the amino acid arginine are 1.8,9.0,and 12.5,respectively.A student at SDSU wants to use ion exchange chromatography to separate lysine from arginine.What pH is likely to work best for this separation?

A) 1) 5
B) 2) 5
C) 5) 5
D) 7) 5
E) 10.5