B.Com

No, the duration of the B.Com is 3 year, and according to New Education Policy 4 year.

Yes, you can appear next year with your junior.

Sri Krishna Arts and Science College is one of the Reputed Colleges of Tamil Nadu with an overall rating of 8.5 out of 10.
It offers Bcom course with the following eligibility criteria: You need to pass 10+2 from a recognised board. Admission is done on merit basis, so you need to get good grades for getting admission into this College. For Bcom, Commerce background will be a preference.

If yes, then you may pursue an MCA. Programme after finishing your B.Com. The applicant must have a bachelor's degree in business, Science, engineering, or an equivalent degree from a recognised university or institute to be eligible for MCA.

B.Com honours including Maths in (2 year) in the preference of your % criteria these are colleges. Since you have asked for the best colleges let us first have a look at the top ten colleges for commerce in India
SRCC
Lady Sri Ram College for women
Loyola College Chennai
Christ University Bengaluru
St. XavierS College Kolkata
Narsee Monjee College of Commerce and Economics
St. Xaviers college Mumbai
St. Joseph College of Commerce
Hans Raj College
Hindu College.

Hi,
After BCOM graduation you can check the following courses:-
Master of Business Administration (MBA)
Masters of Commerce (M.Com)
Chartered Accountant (CA)
Company Secretary (CS)
Chartered Financial Analyst (CFA)
Business Accounting and Taxation (BAT)
Certified Management Accountant (CMA)
Actuarial Science.

You have to give entrace for certain courses and you should get 95% and above for merit based admission.

Hi,
Mass Communication is a vast domain and has a lot to offer such as Journalism (Electronic and Print),
Advertising,
Film Making,
PR,
Acting,
Modeling,
Photography
etc.
And Yes you can easily go for Mass Comm after http://B.Com and enter into Advertising, marketing or any other specialization of your choice.
Top Mass Comm/Media colleges in India are
MICA- Ahmadabad
IIMC- Delhi
XIC- Mumbai
JAMIA- Delhi
SIMC- Pune
School of Broadcasting Journalism- Mumbai
etc.
For the list of institutes in Kolkata, kindly refer to the below link:
Mass Communication & Media colleges in Kolkata
(Simply copy paste the URL in the address bar)
Thanks.
All The Best!

Yes, you can pursue for M.A.

Hi,
The candidate must have studied Commerce in class 11 and 12 with Accountancy, Business Studies, Economics, Maths and English as main subjects. The minimum cut off marks criteria is subject to each college/university's own admission criteria for that year.