Which sentence best adds to the main idea of this paragraph?

Question

The Mayan empire covered the entire Yucatan Peninsula. Today, this area is part of Mexico. The land had many different features such as mountains and rainforests.

Question 4 options:

The Mayans developed solar calendars in 400 BC.

At one time, the empire covered 120,000 square miles

The Mayans studied the stars.

Answer 1

The Mayans developed solar calendars in 400 BC.