If the equation (x/(1 + x2)2 + a(x/(1 + x2) + 3 = 0 has exactly two real roots which are distinct, then the set of possible real values of a is
(A) (- 13/2, 0)
(B) ( -∞, - 13/2)
(C) (-13/2, 13/2)
(D) (13/2, ∞)
Correct option (B) (D)
Explanation: