In the Last Three Decades of the 19th Century,the Long-Run

In the last three decades of the 19th century,the long-run supply track of farm prices

A) indicates a decline in farm prices due to a slowly increasing demand and a more rapidly increasing supply.
B) indicates a decline in farm prices due to a slowly increasing supply and a more rapidly increasing demand.
C) indicates an increase in farm prices due to a slowly increasing supply and a more rapidly increasing demand.
D) indicates relatively constant prices due to the fact that supply and demand were both increasing?at about the same rate.