Union Membership Has Fluctuated During the Last Several Decades

Union membership has fluctuated during the last several decades. Which of the following statements best describes the effect of unions on the share of total output allocated to labor?

A) The share of output going to labor has been virtually constant, even though union membership as a share of the labor force has fluctuated.
B) The share of total output going to labor has followed the same pattern as the business cycle in recent years.
C) The share of total output going to labor rose as union membership rose from 1945 to 1960 and fell as union membership declined during the 1960 through 2000 period.
D) The share of total output going to labor has increased substantially, even though during the last several decades union membership has declined.