Answer:
Primary sources typically have the pronouns "I, he, she, etc.", or specified titles that are typically only used by people of the time period. They also generally talk in the present-term, which, unless it is a historical fiction, all other "secondary sources" will be referring to it in a past-term.
As stated above, Secondary Sources typically from people who write about the event after it has occurred. This may give the benefit of having hindsight and allowing the author to write about the effects of the event. There may be more bias inside this type of writing, however.
In your case, simply choose which type of source your excerpt sounds like, and use that as your answer.
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