Answer:
(Choice B) B These three crops mutually supported each other's growth, a system that spread from present-day Mexico northward into the present-day American Southwest.
Step-by-step explanation:
Three sisters agriculture was an agricultural technique that consisted of planting pumpkins in reverse, beans and corn on the same land and one close to the other. This technique made the production process cheaper, since one culture helped another to grow, without additional processes being necessary.
With this technique, the beans supplied nitrogen to the soil, through its association with nitrogen-producing bacteria. This reduced the need for fertilizers and the three crops could use the benefit. The corn served as a base for the beans to rise and curl up, while the pumpkin spread over the ground and covered the soil, protecting it.