Respuesta :

gmany
[tex]\dfrac{2\pi}{3}\ is\ in\ II\ quadrant[/tex]

[tex]The\ reference\ angle\ is\ \pi-\dfrac{2\pi}{3}=\dfrac{3\pi}{3}-\dfrac{2\pi}{3}=\dfrac{\pi}{3}[/tex]

[tex]\boxed{Answer:\ B.\ \dfrac{\pi}{3}}[/tex]