Which of the Following Statements Concerning the Three-Field Rotation System

Which of the following statements concerning the three-field rotation system is most accurate?

A) Introduced in the 8th century, the three-field rotation added acres to production by leaving only a third of the land unplanted.
B) The three-field system removed land from production by reserving one-third for fallow.
C) The three-field system was rapidly replaced after the 8th century by the two-field system that offered greater flexibility in terms of crop rotation.
D) The three-field system removed fallow fields and replaced them with nitrogen-bearing crops.