Player B is considered all in and Player C must still match the full blind amount and there will just be two possible winning piles depending on who wins. If Player B wins they would win 60 chips per player that paid the big blind and the next high hand would win the rest.
When a player's stack is less than the amount of the small blind, they are automatically considered all-in in the next hand they play, regardless of position.
If the player's stack is larger than the small blind but smaller than the big blind, they will be considered all-in in any position other than the small blind, assuming they fold for their option.
When all-in, the player can only win the amount of their stack, plus that same amount from all of the callers and blinds. If the person has less than the big blind, they can only win the portion of the blind equal to that of their stack.
