am i Saved The following data have been collected for four different cost items. Cost Item W X Y z Cost at 100 units $8,000 $5,000 $6,500 $6,700 Cost at 140 units $10,560 $ 5,000 $ 9,100 $ 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