Final answer:
The use of a fallow period characterizes horticulture, a form of sustainable agriculture that involves letting land rest to replenish soil nutrients.
Step-by-step explanation:
Among the options provided, B. the use of a fallow period best characterizes horticulture. Horticulture is a sustainable form of farming that generally involves extensive or shifting cultivation, with the practice of letting plots of land lie fallow to replenish nutrients naturally. During the fallow period, uncultivated land is left to allow wild vegetation to grow, promoting soil recovery. On the other hand, intensive agriculture is characterized by continuous cultivation of the same plots using labor-intensive methods like plowing, terracing, and irrigation, and is not typically associated with horticulture which relies on rotating crops over various pieces of land.