The formula for the cash conversion cycle is:（ ）

A、Days’ inventory outstanding (DIO) + Days’ sales outstanding (DSO) – Days’ payable outstanding (DPO)
B、Days’ inventory outstanding (DIO) + Days’ sales outstanding (DSO) + Days’ payable outstanding (DPO)
C、Days’ inventory outstanding (DIO) – Days’ sales outstanding (DSO) + Days’ payable outstanding (DPO)
D、Days’ inventory outstanding (DIO) – Days’ sales outstanding (DSO) – Days’ payable outstanding (DPO)