A customer purchased and received $5,000 of goods on credit from Discount Paper Supply on September 1. The customer received the bill on September 13 and mailed a $5,000 check on September 30. Discount Paper Supply received the check on October 4. On which of the following dates should Discount Paper Supply record sales revenue?

A. September 1
B. September 13
C. September 30
D. October 4