Sales and cost data are promising internal secondary data for many research problems. In B2B contexts, the is a gold mine of information.
a. Sales invoice
b. Packing slip
c. Inventory report
d. General ledger
e. Accounts Payable report

The correct answer is letter "A": Sales invoice.

Explanation:

In a Business-to-Business (B2B) transaction sales invoices are provided to record the goods or services exchanged between entities or the record the services rendered from one company to the other. The information included in the invoice reflects the details of the operation such as good or service acquired, quantity, date, and price. This feed could help businesses to predict the future behavior of the other entity or to provide profitable suggestions to them.

one of the appeals of a sole proprietorship is that business expenses are kept separate from your personal income tax return

i would say a penny hope it you