Languages

English is mandatory for marketing people because they need to deal different customers. You can get a job in sales and marketing in Delhi area as most of the people will speak Hindi so you can. But better if you learn English as well.

Yes, you can pursue if you have completed your UG from a recognised board.

Hello Santosh,
Once CBSE has declared your result as pass with whatever subjects that you have taken, you can not give exam for an additional subject nor can you appear for 12th again with different sets of subjects.

The point is if you attempt all the questions, then there will be bonus questions for you to gain extra edge.

Of course dear, you are eligible for the study in Canada with this score. Your score is quite enough to get admission in any good institution and I think you may also try for the scholarship because some colleges might give a scholarship to the students. So if you want to go for it, you should apply immediately.

Please mention the university in which you intend to take admission.