What Is the PI of Valine, Shown Below? (The $\mathrm{p} K_{\mathrm{a}}$

What is the pI of valine, shown below? (the $\mathrm{p} K_{\mathrm{a}}$ 's are shown)

A) 2.32
B) 4.81
C) 5.97
D) 9.62