The correct answer is option 1: Christopher Columbus. Christopher Columbus was the first European to encounter the Cacao plant, which is the plant used to make chocolate.

Option 2: John Cabot, was an Italian explorer who sailed under the English flag. He is known for his voyages to North America, but there is no evidence to suggest that he encountered the Cacao plant or had any direct involvement with chocolate.

Option 3: Hernando Cortez, was a Spanish conquistador who played a major role in the conquest of the Aztec Empire. It is believed that he was the first European to taste chocolate during his time in Mesoamerica, but he was not the first to encounter the Cacao plant.

Option 4: De Leon is not a known historical figure associated with the first encounter of the Cacao plant or chocolate.

Therefore, the correct answer is option 1, Christopher Columbus.