865Q.45:- Draw all possible structures, you'll see that only the structure where no similar groups are at 180° to each other will be optically active. Hence (B) 2.
Q.46:- The answer will be (C) 2. You can see the logic in any book.
Q.47:- The only two structures are the cis and trans forms. Both their mirror images are superimposable on the original structures. Hence (C).
