4. If $\log _{a} \frac{2}{3}<1$, then the range of values for $a$ is $(\quad)$.
A. $\left(\frac{2}{3}, 1\right)$
B. $\left(\frac{2}{3},+\infty\right)$
C. $\left(0, \frac{2}{3}\right) \cup(1,+\infty)$
D. $\left(0, \frac{2}{3}\right) \cup\left(\frac{2}{3},+\infty\right)$
4. C. $\log _{a} \frac{2}{3}1 \\ \frac{2}{3}a,$ we get $01$.



The translation is as follows:

4. C. $\log _{a} \frac{2}{3}1 \\ \frac{2}{3}a,$ we get $01$.