Question

Which would be considered a secondary source about the assassination of Abraham Lincoln?

a diary entry by a witness to the assassination
an interview with a member of the audience at Ford’s Theater where Lincoln was shot
an interview with Booth’s understudy, who was not at Ford’s Theater the night of the assassination
a newspaper article written by a reporter who was in the audience at Ford’s Theatre

Answer 1

The interview with Booth’s understudy, who was not at Ford’s Theater that night.

Reason: a secondary source interprets or reports on an event but is not a direct, contemporaneous eyewitness. The diary entry, the interview with an audience member, and the newspaper by a reporter who was present are all firsthand (primary) accounts.