Question 20Rhombus $ABCD$ has side length $2$ and $\angle B = 120^\circ$. Region $R$ consists of all points inside the rhombus that are closer to vertex $B$ than any of the other three vertices. What is the area of $R?$$\dfrac{\sqrt{3}}{3} $$\dfrac{\sqrt{3}}{2} $$\dfrac{2\sqrt{3}}{3} $$1 + \dfrac{\sqrt{3}}{3} $$2 $