The Contribution of Capital Formation to the Growth of the U.S

The contribution of capital formation to the growth of the U.S. economy

A) was always much smaller than the contribution of labor-input growth.
B) during the 1980s and 1990s, essentially matched the contribution made by capital formation during the 1960s.
C) declined steadily from the mid-1960s to the present.
D) dominated the contribution made by improved productivity throughout the 1980s.
E) b and d.