Question 17A circle centered at $O$ has radius $1$ and contains the point $A.$ Segment $AB$ is tangent to the circle at $A$ and $\angle AOB = \theta.$ If point $C$ lies on $\overline{OA}$ and $BC$ bisects $\angle ABO,$ then what is $OC?$ $\sec^2\theta - \tan\theta$$\dfrac{1}{2}$$\dfrac{\cos^2\theta}{1 + \sin\theta}$$\dfrac{1}{1 + \sin\theta}$$\dfrac{\sin\theta}{\cos^2\theta}$
