"The Workers of Ellis Island" states that a full complement of staff was required to process thousands of immigrants a year. Which sentence from the passage best adds to the central idea that a major workforce was needed at Ellis Island?
Throughout the years, numerous organizations offered volunteer aid to immigrants at Ellis Island.
As a large federal facility employing approximately five hundred employees at a time, Ellis Island was a well-organized workforce.
Besides conducting the line inspection, doctors played no role in deciding the fitness of a person to enter the country.
Both female and male nurses were required to live on the island and were assigned separate quarters.