The best explanation of the Columbian Exchange from the scenarios you provided is Option C: "Domesticated animals such as cattle, horses, pigs, and chickens were introduced to the Americas by European colonizers. Prior to this, very few animals had been domesticated in the Americas."
The Columbian Exchange refers to the widespread transfer of plants, animals, goods, culture, human populations, technology, and disease between the Americas and the Old World (Europe, Asia, and Africa) following Columbus's voyages. This exchange significantly transformed both worlds.
Option C correctly illustrates one of the key aspects of the Columbian Exchange: the introduction of European domesticated animals to the Americas, which had a profound impact on agriculture, transportation, and the lifestyle of indigenous peoples.
While other options touch on elements of the Columbian Exchange, such as the transfer of crops and diseases, Option C focuses specifically on the introduction of domesticated animals, which is a significant aspect of the exchange as defined historically.