1 If the polar equation of a conic section is $\rho=\frac{16}{5-3 \cdot \cos \theta}$, then the polar coordinates of its foci are ( )
A. $(0,0),(6, \pi)$
B. $(-3,0),(3,0)$
C. $(0,0),(3,0)$
D. $(0,0),(6,0)$
1 D. $\rho(0)=8, \rho(\pi)=2$. So $2 c=8-2=6$. The circle has the left focus at the pole $(0,0)$, so the right focus is at $(6,0)$.