If the functions are defined as $$f(x) = \sqrt{x}$$ and $$g(x) = \sqrt{1-x}$$, then what is the common domain of the following functions: $$f+g, f-g, f/g, g/f, g-f$$, where $$(f \pm g)(x) = f(x) \pm g(x)$$, $$(f/g)(x) = \frac{f(x)}{g(x)}$$:

A

$$0 \leq x \leq 1$$

B

$$0 \leq x < 1$$

C

$$0 < x < 1$$

D

$$0 < x \leq 1$$