Read the article "Chicago's International Airports" and answer the question. Chicago is a transportation hub. There are several airports in or near the city. O'Hare International and Midway International are two of the busiest airports in the area. They share many similarities and have some key differences. The city's busiest airport is O'Hare International Airport. It is located northwest of downtown Chicago. To travel between the airport's four terminals, passengers use the automated Airport Transit System. These trains travel over 2.7 miles of track and can carry 2,400 passengers in an hour. Other options for moving between terminals include the pedestrian tunnels and the Terminal Transfer Bus. O'Hare has about 1,028 direct domestic flights and 126 direct international flights each day. In contrast to O'Hare, Midway International Airport is a relatively small airport located southwest of downtown Chicago. The airport only has three concourses, making travel between gates easy and efficient. The facility has approximately 238 direct domestic flights and 12 direct international flights each day.

Both airports feature a variety of artwork, restaurants, and activities for people to experience. The Chicago Public Art Program provides the paintings, murals, sculptures, and exhibits in the corridors of both airports. O'Hare International Airport displays a replica of the fighter plane flown by Lieutenant Commander Edward H. O'Hare, the airport's namesake. Likewise, Midway contains an exhibit of the SBD Dauntless, a dive bomber plane recovered from Lake Michigan. Both airports also have restaurants that feature Chicago delicacies created by local chefs, but only O'Hare has the world's first airport aeroponic garden where foods for the airport restaurants are grown. Passengers waiting at both airports can relax and stretch in the Yoga Room. They can also visit the. While both airports are kid-friendly, O'Hare provides a special interactive children's area. The "Kids on the Fly Exhibit" allows children to play in a model airplane, helicopter, and control center. With the additions of the aeroponic garden and the children's play area, O'Hare offers a unique airport experience

Which sentence in the text helps the reader understand its text structure?

O'Hare has about 1,028 direct domestic flights and 126 direct international flights each day.
While both airports are kid-friendly, O'Hare provides a special interactive children's area.
These trains travel over 2.7 miles of track and can carry 2,400 passengers in an hour.
The airport only has three concourses, making travel between gates easily accessible.