Which of the following describes a major accomplishment of the Inca Empire?

AThe Inca developed a system of math based on Roman numerals.

BThe Inca successfully developed vertical farming in difficult mountainous regions.

CThe Inca wrote on papyrus and kept very accurate genealogical records.

DThe Inca used an accurate calendar based on the tides.

Agriculture was the base of the economy of the Inca empire, where the lands were common. Each family had its land to grow and feed itself. The more members of the family, the greater the amount of land. "The Minka" was the way they worked the land; by this method, the agricultural tasks were carried out through mutual communal aid, in the case that an individual had so much work that he could not do with it, or in the case of orphans, sick and widows. One of the best areas of cultivation of the empire was the Sacred Valley of the Incas.

The potatoes and corn were the basis of the feeding of the Incas, complemented with llama meat and alpaca. Up to 200 different species of potatoes were grown because of their color, shape, and size. They learned to dehydrate the potato to avoid its decomposition; storing them, to ensure the feeding of his army. Their diet was supplemented with vegetables and grains such as olluco, quinoa, tomato, pumpkin, bell peppers, oca, beans, peanuts (from which they extracted oil) and fruits. The Incas used superimposed terraces known as "platforms" to explore the land and water to the maximum, gaining cultivation space on the slopes of the hills.