The correct answer is D.
Explanation
A relative Chronology timeline is a timeline that places each of the events taking as a reference a specific event and when the first event happened in reference to another. According to the above, the correct answer is D. World War I Begins, because that timeline established "June 28, 1914 - Archduke Franz Ferdinand assassinated" as the reference event, and other event are expressed taking to account the first, for example, "One month later - Austro-Hungarian Empire declares war on Serbia". So, the correct answer is D.
