Which expressions describe the end behaviors of the function, f(x)=(3.25)^x +6, modeled by the graph?

a.) As x decreases without bound, f(x) increases without bound.


b.) As x increases without bound, f(x) increases without bound.


c.) As x decreases without bound, f(x) approaches the line y = 6.


d.) As x increases without bound, f(x) approaches the line y = 6.