Which conquistador led the expedition that conquered the Inca Empire?

The expedition that ultimately led to the conquest of the Inca Empire was led by Francisco Pizarro. In the early 16th century, Pizarro and his men faced a numerically superior Inca force, yet through a combination of strategic planning, the capture of the Inca ruler Atahualpa, and the exploitation of existing civil strife within the Inca Empire, Pizarro was able to seize control. His invasion was marked by superior weaponry and the impact of diseases brought by Europeans, which devastated the indigenous population and weakened their societal structures.

Hernán Cortéz is primarily known for his conquest of the Aztec Empire, while the other two figures do not have significant roles in the context of the Inca conquest. Cortez de la Vega does not exist as a notable conquistador in historical accounts, and Bartholomé de las Casas is known more for his work in defending the rights of indigenous peoples than for any military conquest. Hence, Pizarro is clearly associated with the overthrow of the Incas, making him the correct answer.