复数 $z=-3\left(\cos \frac{4}{5} \pi-i \sin \frac{4}{5} \pi\right)$ 的三角表示式为 ）．
A
$3\left(\cos \frac{4}{5} \pi+i \sin \frac{4}{5} \pi\right)$
B
$3\left(\cos \frac{\pi}{5}-i \sin \frac{\pi}{5}\right)$
C
$3\left(\cos \frac{4}{5} \pi-i \sin \frac{4}{5} \pi\right)$
D
$3\left(\cos \frac{\pi}{5}+i \sin \frac{\pi}{5}\right)$
E
F