If lim as x approaches 3 at f(x)/(2x-6)=f'(3)=0 which of the following must be true? i) (3,0) is a critical point of f(x). ii) f(x) has a local minimum at x=3 iii) f(x) is continuous at x=3 a) i only b) ii only c) iii only d) i and iii only e)i ii and iii