Polytechnic

You can do your degree from anywhere. You have to focus on the campus placements.
All the best.

No, you can't. You need to complete Diploma in the same field or a field related to it.

You can get a degree in any field and try for the entrance tests like SSC, UPSC, bank, etc.

You should be a graduate to apply for MBA. Diploma won't work. There is a set hierarchy.

Hi Akash,
The term graduation means Master's degree abroad. You can enroll into a PG course only after you complete your Bachelor degree. Admission process and requirements will depend on the country and university. International applicants must take IELTS or TOEFL to meet language requirements. Kindly, decide where to apply and then visit university requirements on their websites.
Feel free to revert.