In 1933, net investment was -$5.8 billion. This meant that:

a) the economy's capital stock was expanding that year

b) the production of 1933's GDP used by more capital goods than were produced in that year

c) the economy produced a negative amount of capital goods in 1933

d) the economy produced no capital goods at all in 1933

e) gross investment exceeded depreciation by $5.8 billion