I don't understand what I am supposed to do to find what I need to do what the question is asking for. List the following functions in order of the greatest rate of change to the least rate of change as x approaches infinity.

f(x)= 2x

r(x)= x3

s(x)= 3x4

Answer choices:

f(x),s(x),r(x)
s(x),r(x),f(x)
s(x),f(x),r(x)
f(x),r(x),s(x)