100 gold coins
You are presented with 3 chests:
Chest A has been labelled with "100 gold coins."
Chest B has been labelled with "50 gold and 50 silver coins."
Chest C has been labelled with "100 silver coins."
You are told that each label is incorrectly placed because it describes the contents of another chest. To help you determine which chest truly contains 100 gold coins, you are allowed to randomly pick a coin from any chest.
Which chest should you pick a coin from?