A chord of a circle is equal to its radius. The angle subtended by this chord at a point on the circumference is

Answer: Option D

∵ OA = AB = OB (given)

∴ ΔAOB is equilateral triangle
So,
∠AOB = ∠OAB = ∠ABO = 60°
∵ ∠ACB = $$\frac{1}{2}$$ ∠AOB
= $$\frac{1}{2}$$ × 60°
= 30°