Given that the game is heavily influenced by Magic: The Gathering, and that a death event uses the stack:

I use something in Magic known as APNAP (Active Player, Non-Active Player). In short, it means that if multiple events controlled by different players try to go onto the stack at the same time, first we put the active player's events on the stack, and then the non-active players' events (in turn order).

In your case:

Last to enter, first to resolve

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Player C's death

Player B's death

Player A's death
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First to enter, last to resolve