Tracing copies of sales invoices to shipping documents will provide evidence that all
a. shipments to customers were recorded as receivables.
b. billed sales were shipped.
c. debits to the subsidiary accounts receivable ledger are for sales shipped.
d. shipments to customers were billed.

D) Shipments to customer were billed.

Explanation:

A) is wrong because not necessarily all shipments are owed to the company. Some shipments might have been paid already.

B) is wrong because not necessarily all billed sales were shipped. Some billed sales might have taken place in the store, we do not have this information and do not know for sure.

D) Is wrong because the type of account referenced does not have anything to do with the question.

d) social security number

let me know if i am correct or not, so i can edit the answer.