Canada

There is no set limit but more than three or four times is not recommended if your visa is getting rejected every time.

Hi Kashish,
If you crack ISB or IIM, its the best and has global repute. To apply to a Canadian or any foreign business school you must gain some work experience,10 months is okay but they require at least 2 years. Target a reputed university like UBC, UToronto, McGill, etc. otherwise its not worth. You must also take GMAT. So, you decide accordingly, try first in the top Indian business schools, in the meanwhile gain more experience. If IIM or ISB doesn't work out you should definitely try a top ranking university abroad for better prospects.

Which course you should choose is a decision you must take, I can give you options but decide basis your interest and abilities and also your career plans. You must also check other countries since you cannot apply to Canadian universities with three year degree course.But you can see PGD Courses. English, Journalism, Linguistics are some options.

Hi, you have to complete your Bachelor's degree first. You cannot apply to a Masters degree with a diploma, a Bachelor's degree is required.

Hi,
Reapply again if you desire. Work on the points basis which your visa was rejected. Do your homework properly and check why your visa was rejected. Don't worry.

IGNOU don't have study centers abroad. And there is no MCA abroad. Its a degree awarded by Indian universities only.

Thapar University once had a great reputation but not now. So, if you want to choose one of these options only, then go for the abroad option. Else you can try for your home state NIT or some low rank NIT's. Also there are some regional engineering colleges where you could get a seat.