Which question might a historian ask to investigate what happened? How many people are in the photograph?
Where did the sinking take place?
Who took this photograph?
Why did the military use this kind of ship?

Where did the sinking take place?

Explanation:

For a historian, there are certain aspects of the text or information that can authenticate and provide true facts. The most important questions that can ascertain the authenticity of the information are to ask the "who, what, where, how, and why" of the text or information.

And in 'investigating' the photograph of the sinking of the USS Maine in 1898, the question that a historian might ask to investigate is to ask "where the sinking take place". This will provide him/ her the detail about the ship's sinking location and thus help in further investigation of the event.

Thus, the correct answer is the second option.