Final answer:
An account of a nineteenth-century battle in a twenty-first century textbook would not be considered a primary source for a history term paper on Lincoln's Gettysburg Address.
Step-by-step explanation:
A primary source is a firsthand or direct account of an event or topic. It is created by individuals who directly witnessed or participated in the events being described. Based on the given options, an account of a nineteenth-century battle in a twenty-first century textbook would not be considered a primary source for a history term paper on Lincoln's Gettysburg Address. This is because the textbook entry would be a secondary source, as it is a modern interpretation and analysis of the historical event.