The following data have been collected for four different cost items. Cost at Cost 100 Cost at Item units 140 units W $8,000 $10,560 X $5,000 $ 5,000 Y $6,500 $ 9, 100 Z $6,700 $ 8,580 Which of the following classifications of these cost items by cost behavior is correct? A) B) C) D) Cost W variable mixed variable mixed Cost X fixed fixed fixed fixed Cost Y mixed variable variable mixed Cost z variable mixed variable mixed Multiple Choice Choice D Choice B