First blank is easy, we need to figure out what kind of positive goal of economics is to develop tomorrow’s monetary policy. For the second blank it is given in the passage that the economists often rely on conflicting information from the past in (clue : thinking about) their policy ideas for the future, so the option that fits here is excogitating. The third blank should provide a conclusion for this sentence, what will happen when economists rely on often conflicting information to think about the policy ideas for the future and how the critics will see this over scenario. They will see economics as a strange science. Among the options only incongruous matches.