In each question, three meanings numbered I, II and III are given for the Idiom / Phrase bold in the sentence. Out of the given three meanings, only one or two or all the three may be correct. Choose the alternative which best expresses the meaning of the Idiom / Phrase and mark it  as your answer. Even if you do not tell him about your affair, he will come to know as he is a man who can put two and two together .
I. has many sources to know the things
II. calculate very accurately
III. draw a correct inference