In the 1890s Nearly 50 Percent of the Canadian Population

In the 1890s nearly 50 percent of the Canadian population worked on a farm.Today,that number is less than 2 percent.One important explanation for this change is

A) the response to a rising price of labour and a falling relative price of capital.
B) the response to a rising price of capital and a falling relative price of labour.
C) that over long periods of time,labour is always replaced by capital.
D) that over long periods of time,capital is always replaced by labour.
E) that the marginal product of labour was falling over time while the marginal product of capital was rising.