单项选择题

Considerthe following SKU: aisles are 3.6 meters across, the pallets are 0.6meter deep and 1 meter wide, the order quantity is 60 pallets, thepallets of SKU are stackable in 5 pallets. What is the optimal lanedepth of this SKU in floor storage? (  )  
A、4
B、3
C、5
D、6