To evaluate the expression \( \frac{2}{3} (-6 + 4) \), we first need to simplify the part inside the parentheses:
\[ -6 + 4 = -2 \]
Now the expression becomes:
\[ \frac{2}{3} (-2) \]
Next, we multiply:
\[ \frac{2}{3} \times -2 = \frac{2 \times -2}{3} = \frac{-4}{3} \]
Thus, the value of the expression is:
\[ \boxed{-\frac{4}{3}} \]
So the correct answer is D. -4/3.