Observation of a client's inventory is a generally accepted auditing procedure that should be performed whenever it

Question:

Observation of a client's inventory is a generally accepted auditing procedure that should be performed whenever it is possible.
a. What part should the auditors play in planning the physical inventory?
b. Describe the procedures performed by the auditors during their observation of a client's physical inventory.
c. Why do the auditors document their inventory test counts in their working papers?