German Lamps In The US

What will happen to a 60W/230V-bulb from Germany if it is used in the USA at a voltage of 115V?

• a) The bulb will be destroyed because it can only be used at the voltage for which the bulbs have been made.
  
  
• b) The bulb will simply shine as bright as in Germany. Voltage has no influence on the electric power of the bulb. Electric power only depends on the amperage that flows.
  
  
• c) The bulb will shine less bright than in Germany. The lower voltage of 115V results in a lower electric power compared to Germany.
  
  
• d) The bulb will shine brighter than in Germany. The lower voltage of 115V results in a proportional increase of the amperage and therefore in a higher electric power.