Which of the Following Statements Is True

Which of the following statements is true?

A) The share of income going to labor has increased during periods when union membership has increased as a proportion of the U.S. labor force.
B) Inflation in the United States has tended to accelerate as the proportion of the U.S. labor force that is unionized has increased.
C) Higher wages in the unionized sectors of an economy will also push up wages in the nonunion sectors.
D) High real wages cannot be achieved and sustained without increases in output per worker hour.