7. let f: r> r be a differentiable function with f(0) = o. if for all xe r, 1< f(x) < 2, tnen wnich one of the following statements is true on (0, oo)? (a) f is

7. Let f: R> R be a differentiable function with f(0) = O. If for all xe R, 1< f(x) < 2, tnen wnich one of the following statements is true on (0, oo)? (a) f is unbounded (C) f has atleast one zero () f is increasing and bounded d) fis periodic