Let f:R→R be a function such that f(x) = (x² + 2x + 1) / x² + 1.Then
A. f(x) is many-one in (−[infinity],−1)
B. f(x) is one - one in (−[infinity],[infinity])
C. f(x) is many-one in (1,[infinity])
D. f(x) is one - one in [1,[infinity]) but not in (−[infinity],[infinity])]