[单项选择]

Changes in the volume of unemployment are governed by three fundamental forces: the growth of the labor force, the increase in output per man hour, and the growth of total demand for goods and services. Changes in the average hours of work enter in exactly parallel fashion but have been quantitatively less significant. As productivity rises, less labor is required per dollar of national product, or more goods and services can be produced with the same number of man—goods.
If output does not grow, employment will certainly fall; if production increases more rapidly than productivity (less any decline in average hours worked, employment must rise. But the labor force grows, too. Unless gross national product (total final expenditure for goods and services corrected for price changes) rises more rapidly than the sum of productivity increase and labor force growth (again modified for any change in hours of work), the increase in employment will be inadequate to absorb t
A. define the economic terms used in discussion of employment
B. criticize the decisions of past administrations during recession years
C. call for the application of positive economic control policies in the year that lie ahead
D. allay current fears about increasing unemployment