△ABC的两个顶点为A(-4,0)，B(4,0)，△ABC周长为18，则C点轨迹为(    )

A：$\frac{x^2}{25}+\frac{y^2}{9}=1(y\ne 0)$

B：$\frac{x^2}{9}+\frac{y^2}{25}=1(y\ne 0)$

C：$\frac{x^2}{16}+\frac{y^2}{9}=1(y\ne 0)$

D：$\frac{x^2}{9}+\frac{y^2}{16}=1(y\ne 0)$