Is it true that , if any one get C rating then that associate is not eligible for promotion for next 3 year in TCS

Its all in your manager's hand. He just has to fight for you with your Account Head and HR Rest all are excuses by your Manager

Mostly 2 years. Last two years bands are considered for promotion eligibility

Yes. For promotion 1 condition is last 3yr band. Eligibility is either A or B..and based on grade other conditions also apply for promotion.

Atleast for current year not possible. Next year if you get B or A then your manager can fight for it..

I have heard the same thing and in most cases manager doesn't fight for promotion unless you are a critical resource for a project. If you get B next time then also promotion is possible. Your manager should be convinced for your promotion

Is dosent matter which ever band you have