58. Since the postwar period there have been 11 business cycles with an average period of contraction of ________________ and average periods of expansion of _______________.

A. average contraction of 11 months and average expansion of 5 years.

B. average contraction of 11 years and average expansion of 9 months.

C. average contraction of 5 years and average expansion of 9 years.

D. average contraction of 1 year and average expansion of 3 years.