Given f(x)=2xf(x) = 2xf(x)=2x and g(x)=x+4g(x) = x + 4g(x)=x+4, which expression represents the composition f(g(x))f(g(x))f(g(x))?
2x+42x + 42x+4
2x+82x + 82x+8
2x2+8x2x^2 + 8x2x2+8x
x+8x + 8x+8