When Would Management Officials Probably Prefer Centralized (Multi-Plant)bargaining

When would management officials probably prefer centralized (multi-plant) bargaining?

A) when the products at each plant are interdependent (Plant A's product is necessary for Plant B's product) .
B) when the products at each plant are independent of each other (Plant A's product is not necessary to produce Plant B's product) .
C) when both plants' products are labor intensive
D) when neither plants' products are labor intensive
E) when both plants' products are independent and labor intensive