Final answer:
Tarshis's article appears to discuss historical maritime events and the influence of naval power, but without more context, it's not possible to accurately determine the main topic of the article from the multiple-choice options provided.
Step-by-step explanation:
The student's question refers to Tarshis's article, which appears to discuss historical events, specifically pertaining to sea travel and naval power. Based on the provided information, the article may touch upon various historical topics such as naval missions, the sinking of the RMS Lusitania, and possibly the Titanic. However, none of the provided snippets directly clarify that the main topic of Tarshis's article is one of the provided options. Without additional context about the content of Tarshis's article, it is not possible to deduce the main topic accurately. The references to the Samothracian Mysteries, the sinking of the Lusitania, and the influence of naval power suggests a general theme related to maritime history and sea power, but more context is required to select one of the options given in the question.