What event or idea in cabeza de vaca's account did you find the most surprising?

In 1540, Cabeza de Vaca was selected governor of the Spanish settlement on the Rio de la Plata, which is now called Paraguay.His mission was to re-establish the settlement of Buenos Aires in present-day Argentina.He explored the Paraguay river in 1542. The pilgrims threw him out of office in 1545, and he was put on trial, accused of numerous offenses, including usurping the power of the King of Spain. He was considered guilty and passed away short time later.

The answer is d. spain.