Immediately after clearing your 10th you have to start for 11th by choosing any stream among i.e., medical (PCB)/non- medical (PCM)/ Commerce/Arts..Now comes the Question – Which Stream is Best For NDA? Students who choose Science Stream Let us Understand NDA Exam.NDA examination consists two papers viz, paper I Mathematics, Paper II GAT. There if you choose PCMB which is very difficult to select then but if you choose this your both the papers will be covered. But this combination is pretty difficult. It becomes more difficult for the PCB candidates because this is stream suitable for Medical branch. Therefore  PCM