Answer
$\bf{G}$
Work Step by Step
The radius of the arctic circle can be found as:
$r=R \cos L=6471 \cos (66.5^{\circ})=2580.3 \ km$
Next, the circumference can be found as:
$C= 2\pi r=2 (3.142)(2580.3) \approx 16213 \ km$
Therefore, the correct option is $\bf{G}$.
