South America's inland grassland areas, the llanos and the pampas, are a source of A. freshwater for irrigation.
B. shelter for small animals.
C. grazing for cattle.
D. fertile soil for crops.

The Pampas (from the Quechua: pampa, meaning "plain") are fertile South American lowlands that cover more than 1,200,000 square kilometres (460,000 sq mi) and include the Argentine provinces of Buenos Aires, La Pampa, Santa Fe, Entre Ríos, and Córdoba; all of Uruguay; and Brazil's southernmost state, Rio Grande do Sul. The vast plains are a natural region, interrupted only by the low Ventana and Tandil hills, near Bahía Blanca and Tandil (Argentina), with a height of 1,300 m (4,265 ft) and 500 m (1,640 ft), respectively.

Pampas
Natural region
Landscape in the Pampas at eye level. Brazil.
Landscape in the Pampas at eye level. Brazil.

The answer to the question is moraine

Just do the math, then think