I know x real number

I need to find "x" values such that:

2arctan(x) + arcsin(2x/(1+x^2))=pi

A. (0,infinity)

B. (-infinity,-1)U[1, infinity)

C. [1, infinity) right answer

D. [-1,1]

E. [2,infinity)

I tried everything I know.

I found only x=1

I need some ideas,suggestions..