Offline Classes Or Online Classes for NDA Both offline and online classes can be effective for NDA (National Defence Academy) exam preparation. However, each mode of learning has its own advantages and disadvantages. Offline classes provide a classroom experience where you can interact with teachers and peers in person. You can ask questions and get immediate answers, and also receive personalized attention from the instructor. Offline classes also offer a structured learning environment, which can be helpful for students who struggle with self-discipline. On the other hand, online classes offer the convenience of studying from anywhere and at any time.