In the 1850s, the Growth Rate of Real Wages in U.S

In the 1850s, the growth rate of real wages in U.S. manufacturing slowed to nearly zero because

A) the demand for manufacturing labor and the supply of manufacturing labor increased by approximately the same amount during this period.
B) the demand for manufacturing labor and the supply of manufacturing labor decreased by approximately the same amount during this period.
C) the demand for manufacturing labor increased more rapidly than the supply of manufacturing labor during this period.
D) the demand for manufacturing labor increased while the supply of manufacturing labor decreased during this period.