I. The average value of the exponential function $$f(x)=e^{-x}$$ on the interval [0, L] is calculated as $$\frac{1}{L}\int_0^L e^{-x}dx$$.

II. For any positive value of L, the average value of $$e^{-x}$$ on [0, L] is always less than $$e^{-L/2}$$.

III. As L approaches infinity, the average value of $$e^{-x}$$ over [0, L] tends to 0.

Which of the above statements regarding the average value of the exponential decay function is/are true?