Find the range of the function f(x)=1x2+4+3f(x) = \frac{1}{x^2+4} + 3f(x)=x2+41+3.
(3,3.25](3, 3.25](3,3.25]
(3,4](3, 4](3,4]
[3,∞)[3, \infty)[3,∞)
[3,3.25)[3, 3.25)[3,3.25)