5. Let $F_1, F_2$ be the two foci of hyperbola $C$. Let $P$ be a point on $C$, and $\angle F_1 P F_2 = 60°$, $|PF_1| = 3|PF_2|$. Then the eccentricity of $C$ is A. $\frac{\sqrt{7}}{2}$ B. $\frac{\sqrt{13}}{2}$ C. $\sqrt{7}$ D. $\sqrt{13}$
5. Let $F_1, F_2$ be the two foci of hyperbola $C$. Let $P$ be a point on $C$, and $\angle F_1 P F_2 = 60°$, $|PF_1| = 3|PF_2|$. Then the eccentricity of $C$ is\\
A. $\frac{\sqrt{7}}{2}$\\
B. $\frac{\sqrt{13}}{2}$\\
C. $\sqrt{7}$\\
D. $\sqrt{13}$