To gain assurance that all inventory items in a client's inventory listing schedule are valid, an auditor most likely would trace

a. Inventory tags noted during the auditor's observation to items listed in the inventory listing schedule.

b. Inventory tags noted during the auditor's observation to items listed in receiving reports and vendors' invoices.

c. Items listed in the inventory listing schedule to inventory tags and the auditor's recorded count sheets.

d. Items listed in receiving reports and vendors' invoices to the inventory listing schedule.