Which diagram describes a cause-and-effect relationship between some of the events on the timeline?
History of Inca Empire, 1438 - 1572
1438: Pachacuti becomes the leader of the Incas.
1476: The Inca Empire defeats the Chuma Empire.
1493: The Inca Empire reaches its peak.
1520: Spanish explorers arrive in South America.
1525: Many Incas die from smallpox.
1533: The Inca emperor Atahualpa is executed by the Spanish.
1572: The Inca Empire ends.