In the 20th-Century, the Structure of US Agriculture Trended Towards

In the 20th-Century, the structure of US Agriculture trended towards

A) a randomly-changing structure - the number and size of US farms varied so unpredictably , that it became difficult to forecast the trend of farm numbers and farm size in much of the 20th-Century.
B) a very stable structure - the number of farms and the average size of farm (measured in acres and/or revenues) stayed fairly constant throughout the entire era.
C) a less concentrated structure - the number of farms increased and the average size of farm (measured in acres and/or revenues) decreased.
D) a cyclical structure - the number and size of US farms decreased in the first half of the century, but reversed the trend and increased in numbers and size in the last half of the 20th-Century.
E) a more concentrated structure - the number of farms decreased and the average size of farm (measured in acres and/or revenues) increased.