Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.

[Q]: On January 26, 1879, who was granted a patent for r an electric lamp using a carbon filament or strip coiled and connected to platina contact wires?
[A]: incandescent light bulb


[Q]: Which former Blue Peter presenter died in April 2004, aged 41?
[A]: blue peter


[Q]: Which army besieged Paris from 18 September 1870 for 4 months?
[A]:
siege of paris