I believe your answer is C. incandescent bulb
A geologist studies the earth's history.
Did any of them feature older actors? ... Each culture has a certain set of expectations and assumptions about aging, all of ... In North America, the experience of being elderly has changed greatly over the past century.
It's one of the following:
1) Social Science
2) Sociology
3) Anthropology
I'm leaning towards social science, but there are far too many variables in what constitutes a probable, correct response to this particular question.