Which of these is the graph of a constant function?
f(x)=xf(x) = xf(x)=x
f(x)=5f(x) = 5f(x)=5
f(x)=3x+1f(x) = 3x + 1f(x)=3x+1
f(x)=x2f(x) = x^2f(x)=x2