For those who are aiming for just selection, NCERT is sufficient for you, you need not buy any other book(s).
For those who are aiming for a rank around 1000 must buy the best book for organic chemistry - LG Wade
- LG Wade organic chemistry
For those who want nothing less than an under 100 rank, you must buy additionally the book by MS chauhan (which is really a big gun to solve)
- MS Chauhan
I did not find a proper link on the internet for this book, kindly search in the local store. This book contains just the problems and no theory.