Villagers in Xiaogang, China, Produced More Rice Than Those in Surrounding

Villagers in Xiaogang, China, produced more rice than those in surrounding villages because:

A) they had better farmland.
B) they were given better seeds.
C) they were able to keep the output they produced individually.
D) they made each family responsible for a certain, higher quota of rice production.
E) ​they had common ownership over the rice produced.