45.
A:
Amino acids tend to be least soluble in water at their isoelectric point.
B:
Sickle cell Hb and the normal Hb have same value of negative charge.
C:
Amino acids are made visible on the chromatograms by treatment with ninhydrin.
D:
The net charge on an amino acid is a function of the pH of the solution.
The answer is: B