Read this excerpt from A Night to Remember.

This was the era when gentlemen formally offered their services to "unprotected ladies" at the start of an Atlantic voyage. Tonight the courtesy came in handy.

How does the author support this central idea?

by describing the behavior of the women who are leaving the ship
by giving descriptions of personal experiences and conversations
by explaining the dangers involved in voyaging across the Atlantic
by offering an opinion about the need for protection from gentlemen