Mega Manufacturing makes six different models of widget. All six models are assembled on the same equipment, but this equipment needs extensive recalibration each time the firm switches production from one model to another. Based solely on this information, which of the following activity cost pools would Mega most likely want to include in an ABC system?

A : A cost pool for product design.

B : A cost pool for production planning.

C : A cost pool for models produced.

D : A cost pool for machinery setup.