A Blinds/Button Question

[J Palo]

I will put my question into a hypothetical situation.

Player A - Seat 1 (Button)
Player B - Seat 2 (Small Blind)
Player C - Seat 3 (Big Blind)
Player D - Seat 4

This is a Tournament. If Player B or C are eliminated, do the blinds move or does the button move? Basically how are the Blinds and Button moved in these situations?

Thanks for your help. I have been playing for awhile and this question always comes up in my home game. For some reason its one of those things nobody really knows. We usually always move the button and the BB would become the button. But maybe there is a dead button for one hand until the blinds are moved. Please let me know the deal.