If f : R→R and F(x) =$\frac{\sin \left(\mathrm{\pi }\right\{\mathrm{x}\left\}\right)}{{\mathrm{X}}^4+3{\mathrm{x}}^2+7}$, Where { } is a fractional part of x , then

• A

  f is injective

• B

  f is not one -one and non -constant

• C

  f is a surjective

• D

  f is a zero function