Given:
The figure of a circle O.
To find:
The value of x.
Solution:
First, label some points on the given figure as shown below.
In triangle BOC,
(Radii of same circle)
It means
is an isosceles triangle and the base angles of an isosceles triangles are congruent. So,



In triangle
,
(Angle sum property)




Now,



Using the central angle theorem, we get



Therefore, the correct option is B.