7.The isoelectronic point of an amino acid is the point where (A)the pKa of the a-carboxylic acid is the same as the pK, of the a-amino group. (B)the a-carboxylic acid is protonated and the a-amino group is unprotonated. (C)the solubility of the amino acid is maximized. (D)the a-carboxylic acid and the a-amino group are both half protonated.(E)the amino acid carries no net electrical charge.