If f(x)=3x2f(x) = 3x^2f(x)=3x2 and g(x)=xg(x) = \sqrt{x}g(x)=x, what is the domain of the composite function h(x)=(f∘g)(x)h(x) = (f \circ g)(x)h(x)=(f∘g)(x)?
All real numbers
x > 0
x \ge 0
x \neq 0