Concept:The phrasal verb must match the meaning of successfully handling a difficult task or responsibility.Explanation:'Carry it off' means to succeed in doing something difficult or to handle a situation well.'Carry it forward' means to continue or advance something, which does not fit the idea of using experience and authority.'Cart it off' means to take something away, and 'carve it out' means to create or obtain something by effort; neither fits the sentence.Thus, the experience and authority enable him to carry it off.Answer:The correct answer is 'carry it off'.