Bachelors

Yes, you can pursue Bachelor's degree after completing Diploma.

You may intend to prepare early for IAS. In such a case, join in BA. By that way, your study for IAS can be intense. You can also increase your General Awareness.

Hi Anurag,
Different universities and colleges have different entry requirements. NIOS is recognized so if you meet the college requirements they will accept you.

Please clarify your question. Why do you want to change your stream if you have already planned to pursue UG in commerce?

Hi Balaji,
If you have great scores you should try Germany, a hub for automobiles and mechanics. Also, education is almost free, if not free then very cheap and they would charge only semester fees. Additionally, living expenses would be incurred. Check RWTH Aachen, University of Heidelberg, University of Stuttgart, etc. You may also check universities in Spain and Netherlands.

Apart from NDA, you can also go for the other options which are available like you can give the exam of SSR for Indian navy after 10+2 (science stream). So, there are various gates for the entry.