How it fits together
An innovation may build on earlier discoveries and improve through the work of many people. The light bulb, airplane, and integrated circuit are examples in the official civics list. The question asks for an example of an innovation, not a full account of who invented every part.
A closer look
Use the broad accepted example for the test, while remembering that historical credit can be shared. Developing a useful technology often involves experiments, manufacturing, and systems that make it practical, rather than one isolated moment of inspiration.