A circle C touches the line x = 2y at the point (2,1) and intersects the circle C₁ : x² + y² + 2y – 5 = 0 at two points P and Q such that PQ is a diameter of C₁. Then the diameter of C is :
(A) 7√5
(B) 15
(C) √ 285
(D) 4 √ 15