Operations

There's no technical way to enter the field. But while in MBA, you can focus on international business and trade relations subjects. You could try interning at a port operations. This would be a great help for you in terms of all the over understanding of trade and challenges related to it. You could even try a sales profile in an industry where you need to understand all the different kinds of companies and their products, like an insurance industry. Good luck!

Both are equally good, challenging and rewarding in their own ways. What matters more is which stream you want to pursue while doing your MBA. https://www.shiksha.com/mba/articles/top-5-mba-specializations-in-india-blogId-3223.

The duration will be 2-years only for PGDM programme. If I talk about the fee structure, the fact is that it varies from one college to another.
Best colleges for operations is NITIE and SIOM so I would suggest going for these colleges if you are really inclined towards operations.

I suggest you should study I and II semester of the programme and decide about it. The exposure to functional areas is a must to understand your own pulse. Every specialization has its own strengths as well as weaknesses in terms of career and opportunities available in the market. But, many students have myths that have no value. The selection of specialization is a careful calibration that needs to be addressed after first year of your exposure to all the functional areas of management. Do not bother about it too much.

Eligibility for M.Sc in Operations and Theatre Technology
As a minimum criterion of eligibility, aspiring candidates need to have completed graduation in Science (B.Sc.) stream from a recognised university with Physics, Chemistry and Biology as main subjects, and with a minimum aggregate score of 45%.
Admission process for the course may vary between institutes. A few top institutes also have an entrance test and round of personal interview in place for admission to the course. Students are selected based on the obtained merit. A few institutes also offer direct admission to the course.