Under the Bargaining Power Model,when Is the Union's Bargaining Power

Under the bargaining power model,when is the union's bargaining power increased?

A) it costs more for management to disagree than agree with the union
B) it costs more for management to agree than to disagree with the union
C) it costs more for the union to agree than disagree with management
D) it costs less for the union to agree than disagree with management
E) it costs less for management to disagree than to agree with the union