A circle having centre at (0, 0) and radius equal to 'a' meets the x - axis at P and Q. A(α) and B(β) are points on this circle such that α – β = 2γ, where γ is a constant. Then locus of the point of intersection of PA and QB is
(A) x2 – y2 – 2ay tan γ = a2
(B) x2 + y2 – 2ay tan γ = a2
(C) x2 + y2 + 2ay tan γ = a2
(D) x2 – y2 + 2ay tan γ = a