Direction : Read the passage carefully and answer the questions given below :

Passage II

Christopher Columbus of Spain set foot in the New World in 1492. Six years later, Vasco da Gama of Portugal reached India. During the next two centuries the Spaniards and the Portuguese actively transferred, not only to Europe but to many parts of Asia as well, a number of plant species which they encountered in South and central America, in expectation of their potential either as food or as medicine. These plants had been developed to a high degree by the Maya and Inca civilizations of these regions. Of these, the potato (Solanum tuberosum) is believed to have been domesticated in terraced slopes on the high plateau of Bolivia-Peru in South America, sometime between 5000 and 2000 BC. Europeans first saw potatoes in South America in 1537, and around 1570 a Spanish ship brought the first potatoes to Europe. Though termed papa in South America, they were incorrectly called batata (the name for the sweet potato) when John Gerard first described them in English in 1597, and this name stuck. An 1860 report states that by 1780, potatoes, peas and beans were in high repute as foods in Calcutta, and that the Dutch are said to have been the first to introduce the culture of potatoes, which was received from their settlement of the Cape of Good Hope. From there the British received annually the seeds of every kind of vegetable useful at the table, as well as several plants of which there appears to be much need, especially various kinds of pot herbs.

According to this passage, how long ago was the potato domesticated in South America ?