sliver spoon is a good conducter because it easily heats up. like for example, you put a sliver spoon in a bowl of hot soup and you hold it up and touch the spoon, it's really hot.
All three have the same current, so that is not a factor. Wattage (power) is E*I or i^2 R. The higher the resistance, the more power dissipated. The answer is R3 because it has the highest resistance. R3 <<<< ===== answer.
