Economics

No, you can't economic honours. Because for economic honours for maths is compulsory.

B.com, B.com(h), BBA,BA (economic) are some courses which you can pursue after 12th

Questiona are very generic:
Logical reasoning
GK
Stream knowledge

Hi Akanksha, LSE is one of the world's top ranked business schools. You can be rest assured about the recognition. Your class performance, communication, networking and leaderships skills and your overall potential will be critical when you finally look for a job.

First it is important for you to understand the difference between M.Sc and MA. M.Sc is much more into research. If you are interested in research I suggest you to do M.Sc.

If you are interested in law and economics then opt B.A. and prepare yourself for UPSC.Since you are interested in this field you will definitely excel.But you have taken 3 years leave,it would be somewhat difficult for you to backup but don't loose hope.Give your best.Try to understand the concepts of syllabus of UPSC and then march towards your goal.
Hope this helps u and all the best!!!