what book should we prefer for general knowledge for students appearing in NDA 2021 AND 2022 ( ARIHANT GK OR LUCENT GK ) and what books should we prefer for social science??

To do best in the examination, the most important step is to choose the best book. Both Lucent's General Knowledge and Arihant's General Knowledge are great in the field. You can choose any of these two. However, experts and top educators mostly recommend Arihant's General Knowledge. But Lucent's GK is also good. For Social sciences, you can rely on Ram Ahuja's Social Problems in India (Indian Socity - GS1). For History section in the General Ability Section, you can follow Bipin Chandra's History of Modern India. Go through the article for more information regarding the best books for preparation http://competition.careers360.com/articles/best-books-prepare-for-nda