Points A and C lie on a circle centered at O, each of \overline{B A} and \overline{B C} are tangent to the circle, and \triangle A B C is equilateral. The circle intersects \overline{B O} at D. What is \dfrac{B D}{B O} ?

**Answer Choices**

A. \dfrac{\sqrt{2}}{3}

B. \dfrac{1}{2}

C. \dfrac{\sqrt{3}}{3}

D. \dfrac{\sqrt{2}}{2}

E. \dfrac{\sqrt{3}}{2}