Do You Know the Difference Between For and Since?

Hello everyone. I’ve created a new video on my Youtube channel that goes through the difference for and since.

Here is the video: http://www.youtube.com/watch?v=CVyK7Sl1zFA (copy and paste).

Then, complete the following sentence:

- I lived there ____.

a) for two years
b) since 1999 

a.Because the period is simple past and it’s an action that finished in the past and didn’t continue. Am I right?