Hello Tarun

You should select the best books which cover all the topics for NDA 2019 preparation. Pathfinder for NDA & NA National Defence Academy Naval Academy Entrance Examination by Arihant is a decent book.
Other important books which you can refer for strengthening your basics and resolving your doubts are-

Let's Crack NDA Exam - National Defence Academy & Naval Academy Examination
Study Package for NDA/NA Entrance Exam
Chapterwise-Sectionwise Solved Papers NDA & NA

You can go through the link below to check subject wise best books and preparation tips-

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https://competition.careers360.com/articles/best-books-prepare-for-nda

Good Luck!