If f(x)=⌊x⌋f(x) = \lfloor x \rfloorf(x)=⌊x⌋ and g(x)=xg(x) = \sqrt{x}g(x)=x, find the domain of f(g(x))f(g(x))f(g(x)) for x∈[0,9]x \in [0, 9]x∈[0,9].
[0,9][0, 9][0,9]
[0,3)[0, 3)[0,3)
[0,3][0, 3][0,3]
all non-negative integers