2. Given $a=\log _{8} 5, b=\log _{4} 3, c=\frac{2}{3}$, then the size relationship of $a, b, c$ is ( )
A: $\quad a>b>c$
B: $\quad b>c>a$
C: $\quad b>a>c$
D: $\quad c>b>a$
Answer $\mathrm{C}$.
Analysis $a=\log _{2} \sqrt[3]{5}>1, b=\log _{2} \sqrt{3}>1, c=\frac{2}{3}<1, \because 5^{2}<3^{3}, \therefore \sqrt[3]{5}<\sqrt{3}, \therefore c<a<b$.