Correct Option: B

According to question , we draw a figure of triangle ABC circumscribes a circle with centre O

In ∆ ABC,
Given , ∠ BAC = 85° , ∠ BCA = 75°
∴ ∠ABC + ∠ BAC + ∠ BCA = 180°
∴ ∠ABC = 180° – 85° – 75° = 20°
We can say that the angle subtended by an arc of a circle at the centre is double the angle subtended by it at any point on the remaining part of the circle.
∴ ∠AOC = ∠ABC = 40°
∴ OA = OC = radii
In ∆ OAC, ∠OAC = ∠OCA
(The angles at the base of an isosceles triangle are equal)
∠OAC + ∠OCA = 180° – 40° = 140°