Secondary source? A. A diary entry written by a person who witnessed an event B. A photograph taken at an event by a trained historian C. A timeline describing the major parts of an event D. A description of an event written long after it took place

The correct answer is D because, a Primary source is information gathered first hand, getting the information yourself while the event takes place or a textual source written while it happened. This means that getting your information from someone by word of mouth, or gathering it from several textual sources that were written after the event takes place, is a secondary source.

So the answer is D because it was written long after the event actually took place.