Which of the Following Statements Is Not True of Han

Which of the following statements is not true of Han Chinese farming?

A) An improved harness made it easier to use horses in the field.
B) The Chinese developed a systematic way to use animal manure for fertilizer.
C) Farming was confined to land already in cultivation, as the newly conquered lands to the north and west were not suitable for agriculture.
D) As iron became more available, farmers were able to increase their use of the plow.
E) For its time, Han agriculture was the most advanced in the world.