The Tripeptide Alanyllysylaspartate Contains Four Ionizable Groups with PK_as of 2.0,3.9,9.9,and

The tripeptide alanyllysylaspartate contains four ionizable groups with pK_as of 2.0,3.9,9.9,and 10.5.Calculate the pI for this molecule.

A) 3) 0
B) 6) 0
C) 6) 2
D) 10.2
E) none of the above