4. (2+2 points) Let a > 0 and 33111013) :1: if a: at 0 a w=0' M) = { Which of the following MUST be true? (I) limit-r0 f0\") = a (II) 3f(a:) = 1 has a solution in (0,1) (a) (I) ONLY (b) (II) ONLY (0) Both of them ((1) None of them