Raven purchases a new cell phone for $700 that depreciates annually. The value of her cell phone per year can be modeled by the exponential function f(x) = 700(0.86)x, where x is the number of years. What is the range of this exponential function in terms of the context of the problem?

(0, 700]
[0, ∞)
(700, ∞)
ℝ