P and Q are the focus of the ellipse $\frac{{\mathrm{x}}^2}{{\mathrm{a}}^2}+\frac{{\mathrm{y}}^2}{{\mathrm{b}}^2}=1$  and B is an end of the minor axis. If PBQ is an equilateral triangle, then the eccentricity of the ellipse is

• A

  $1/\sqrt{2}$

• B

  1/3

• C

  1/2

• D

  $\sqrt{3}/2$