Why Has There Been a Movement, Over Time, of the Canadian

Multiple Choice

Why has there been a movement, over time, of the Canadian population from farms to urban areas?  

A)  because individual members of farm families are specializing in particular sets of tasks 
B)  because of a sharp increase in farm productivity 
C)  because of a decline in the demand for labour in urban areas 
D)  because of a sharp decline in the demand for agricultural products