D. 120°
The angle between them should be 120° because in that case the figure formed by the intersection point of pair of tangent, the two end points of those-two radii tangents are drawn) and the centre of the circle is a quadrilateral.
From figure it is quadrilateral,
∠POQ + ∠PRQ = 180° [∴ sum of opposite angles are 180°]
60°+ θ = 180°
θ = 120
Hence, the required angle between them is 120°.