Union Membership in the United States Has Declined Since the Mid-1950's.All

Multiple Choice

Union membership in the United States has declined since the mid-1950's.All of the following factors have attributed to this decline except:

A) increase in women in the workforce who are more likely to work part-time.
B) improved wages and benefits.
C) shift from a manufacturing-based economy to a service-based economy.
D) increase in small firms.