Final answer:
Hernando de Soto began his 1539 expedition with a large group of 600 men. Only a little over three hundred survived to return to Mexico City following de Soto's death in 1542. The correct answer is C) 600.
Step-by-step explanation:
The number of explorers Hernando de Soto had on his expedition to what is today the southeastern United States was quite substantial. Initially, de Soto was accompanied by a large group of 600 men when he set out in 1539 to explore and conquer new lands, hoping to find wealth just as Cortés and Pizarro had in their conquests.
Sadly, the undertaking was arduous and fraught with challenges, including disease and resistance from native populations.
By the end of the expedition, after de Soto's death in 1542, less than half of the original group survived to return to Mexico City. Thus, the correct answer to the question is C) 600 explorers.