West Coast Dockworkers Were Locked Out of Their Jobs in 29

West coast dockworkers were locked out of their jobs in 29 west coast ports. Because many consumer goods used in the U.S. are transported from Asia to the U.S. through these ports, the lockout could have damaged the U.S. economy and security if allowed to continue. The President ordered the dockworkers back to work and both sides were ordered back to the bargaining table. Which of the following statements is the most accurate conclusion about the outcome of the labor dispute between the dockworkers union and shipping companies on the west coast? The dispute between the dockworkers and shipping companies showed that:

A) the only effective weapon unions now have in labor-management disputes is the threat of a strike.
B) arbitration is the only effective way to settle labor-management disputes in industries that are critical to the nation's safety or security.
C) the Taft-Hartley Act must be invoked when there is a risk to national security.
D) unions have become so powerful that they can shut down the entire U.S. economy.