If f(x)=x2f(x) = x^2f(x)=x2 and g(x)=xg(x) = \sqrt{x}g(x)=x, which of the following is true for x≥0x \geq 0x≥0?
g(f(x))=x2g(f(x)) = x^2g(f(x))=x2
g(f(x))=xg(f(x)) = xg(f(x))=x
g(f(x))=xg(f(x)) = \sqrt{x}g(f(x))=x
g(f(x))=x4g(f(x)) = x^4g(f(x))=x4