2. Given an arithmetic sequence $\left\{a_{n}\right\}$ with a non-zero common difference, and $a_{2}, a_{3}, a_{9}$ form a geometric sequence, then the value of $\frac{a_{4}+a_{5}+a_{6}}{a_{2}+a_{3}+a_{4}}$ is
A. $\frac{8}{3}$
B. $\frac{7}{3}$
C. 3
D. $\frac{5}{3}$
Let the common difference of the sequence $\left\{a_{n}\right\}$ be $d,\left(a_{1}+2 d\right)^{2}=\left(a_{1}+d\right)\left(a_{1}+8 d\right) \Rightarrow 5 a_{1} d+4 d^{2}=0$ $\Rightarrow a_{1}=-\frac{4}{5} d \Rightarrow a_{n}=\frac{5 n-9}{5} d$. Therefore, $\frac{a_{4}+a_{5}+a_{6}}{a_{2}+a_{3}+a_{4}}=\frac{11+16+21}{1+6+11}=\frac{8}{3}$, choose $A$.