I don't know either.
You've given zero information, other than the fact that you need help. It is not possible to answer your question at this point in time.
If you want a useful answer, tell us what connections are available on your TV and which MacBook you have. Go to the Apple Menu and click on "About This Mac" and then click on "More Info..." In the resulting window, one of the lines will say "Model Identifier: MacBook x,x" where x is a number. Mine is a MacBook 3,1.
Once you post that information, we'll easily be able to tell you what cord you need.