For the most part, passengers in first or second-class accommodations disembarked in New York and entered the United States. Those in third class or "steerage" had a very different experience throughout the journey. First, they were crammed below deck in filthy conditions with everything they owned.

From the port in New York, they were ferried to Ellis Island, where they might be held for hours, days, weeks, and in some cases months. The point of the inspections was to identify undesirables, such as those with a criminal record, the mentally ill, or those who could not support themselves financially. It was a frightening experience for the travelers.

Which best describe’s the author’s purpose in this excerpt?

to demonstrate the difficult conditions many immigrants faced
to describe the different sections of ocean liners in the 1800s
to show why many people were reluctant to come to America
to explain how immigration has changed since the 1800s