Mark the correct answer and explain your answer:

At the isoelectric pH of a protein, the solubility of the protein is minimal because:

A. At this pH, the electrostatic forces of attraction between the protein molecules are maximum, so the protein molecules tend to sink.

B. At this pH the protein does not carry charges, therefore there are no attractive forces between the water and the protein molecules and it sinks.

C. At this pH, strong repulsive forces are created between the protein molecules and therefore the protein sinks.

D. The question is misleading, at the isoelectric pH the solubility of the protein is actually maximum.