At one point in the video Alex discovered that there were many parts waiting at final assembly. Why wasn't the operation using those parts to ship orders? Group of answer choices The final assembly was the bottleneck so parts were naturally piling up in front of it. These were parts that could not be used because of poor quality. These were excess parts not needed for any orders. These were extra parts acquired by purchasing to serve as safety stock. They were missing other necessary parts to complete the orders